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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
__________________
FORM 10-K
__________________
  (Mark One)

 x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
For the fiscal year ended December 31, 2017
OR

o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from _____________ to _____________
 
Commission File Number: 001-36384
__________________


THE RUBICON PROJECT, INC.
(Exact name of registrant as specified in its charter)
 __________________
Delaware
 
20-8881738
(State or other jurisdiction of incorporation or organization)
 
(I.R.S. Employer Identification No.)
 
 
 
12181 Bluff Creek Drive, 4th Floor
Los Angeles, CA 90094
(Address of principal executive offices, including zip code)
 
 
 
Registrant's telephone number, including area code:
 
(310) 207-0272
 
 
 
 
Securities registered pursuant to Section 12(b) of the Act:
 
 
 
Title of each class
 
Name of each exchange on which registered
Common Stock, $0.00001 par value
 
New York Stock Exchange
 
 
 
Securities registered pursuant to Section 12(g) of the Act:
 
None
 
 __________________
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.   Yes ¨   No x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.   Yes ¨ No x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.   Yes x    No ¨
 
Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).   Yes x    No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of the registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ¨

  
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer,a smaller reporting company, or an emerging growth company.  See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.
Large accelerated filer  ¨
 
Accelerated filer x
 
 
 
Non-accelerated filer ¨ 
(Do not check if a smaller reporting company)
 
Smaller reporting company ¨
 
 
 
Emerging growth company x
 
 
 
 
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. x

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).   o Yes x  No

As of June 30, 2017, the aggregate market value of shares held by non-affiliates of the registrant (based on the closing sales price of such shares on the New York Stock Exchange on June 30, 2017) was approximately $228.2 million.
 
Indicate the number of shares outstanding of each of the registrant's classes of common stock, as of the latest practicable date.
Class
 
Outstanding as of March 8, 2018
Common Stock, $0.00001 par value
 
50,254,718

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant's Proxy Statement for the 2018 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant's fiscal year ended December 31, 2017.



Table of Contents

THE RUBICON PROJECT, INC.
FORM 10-K
FOR THE FISCAL YEAR ENDED DECEMBER 31, 2017
TABLE OF CONTENTS
 
 
Page
No.
 
 
 
Part I
 
 
Item 1.
Item 1A.
Item 1B.
Item 2.
Item 3.
Item 4.
 
 
 
Part II
 
 
Item 5.
Item 6.
Item 7.
Item 7A.
Item 8.
Item 9.
Item 9A.
Item 9B.
 
 
 
Part III
 
 
Item 10.
Item 11.
Item 12.
Item 13.
Item 14.
 
 
 
Part IV
 
 
Item 15.
Item 16.
 

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SPECIAL NOTE ABOUT FORWARD-LOOKING STATEMENTS
This Annual Report on Form 10-K and related statements by the Company contain forward-looking statements, including statements based upon or relating to our expectations, assumptions, estimates, and projections. In some cases, you can identify forward-looking statements by terms such as "may," "might," "will," "objective," "intend," "should," "could," "can," "would," "expect," "believe," "design," "anticipate," "estimate," "predict," "potential," "plan" or the negative of these terms, and similar expressions. Forward-looking statements may include, but are not limited to, statements concerning our anticipated financial performance, including, without limitation, revenue, advertising spend, non-GAAP net revenue, profitability, net income (loss), Adjusted EBITDA, earnings per share, and cash flow; strategic objectives, including focus on header bidding, mobile, video, and private marketplace opportunities; investments in our business; development of our technology; introduction of new offerings; the impact of our acquisition of nToggle and its traffic shaping technology on our business; the effects of our cost reduction initiatives; scope and duration of client relationships; the fees we may charge in the future; business mix and expansion of our mobile, video, and private marketplace offerings; sales growth; client utilization of our offerings; our competitive differentiation; our market share and leadership position in the industry; market conditions, trends, and opportunities; user reach; certain statements regarding future operational performance measures including ad requests, fill rate, paid impressions, average CPM, take rate, and advertising spend; and factors that could affect these and other aspects of our business. These statements are not guarantees of future performance; they reflect our current views with respect to future events and are based on assumptions and estimates and subject to known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from expectations or results projected or implied by forward-looking statements. These risks include, but are not limited to:
our ability to grow and to manage any growth effectively;
our ability to develop innovative new technologies and remain a market leader;
our ability to attract and retain buyers and sellers and increase our business with them;
our vulnerability to loss of, or reduction in spending by, buyers;
our ability to maintain and grow a supply of advertising inventory from sellers;
the effect on the advertising market and our business from difficult economic conditions;
the freedom of buyers and sellers to direct their spending and inventory to competing sources of inventory and demand;
our ability to use our solution to purchase and sell higher value advertising and to expand the use of our solution by buyers and sellers utilizing evolving digital media platforms;
our ability to introduce new offerings and bring them to market in a timely manner in response to client demands and industry trends, including shifts in digital advertising growth from display to mobile channels;
the increased prevalence of header bidding and its effect on our competitive position;
uncertainty of our estimates and expectations associated with new offerings, including header bidding, private marketplace, mobile, video, guaranteed audience solutions, and traffic shaping;
declining fees and take rate and the need to grow through advertising spend increases rather than fee increases;
our ability to compensate for a reduced take rate by increasing the volume and/or value of transactions on our platform;
our vulnerability to the depletion of our cash resources as revenue declines with the reduction in our take rate and as we incur additional investments in technology required to support the increased volume of transactions on our exchange;
our ability to support our growth objectives with reduced resources from our cost reduction initiatives;
our ability to raise additional capital if needed and/or to renew our working capital line of credit;
our limited operating history and history of losses;
our ability to continue to expand into new geographic markets;
our ability to adapt effectively to shifts in digital advertising to mobile and video channels;
increased prevalence of ad blocking technologies;
the slowing growth rate of online digital display advertising;
the growing percentage of online and mobile advertising spending captured by owned and operated sites (such as Facebook and Google);
the effects, including loss of market share, of increased competition in our market and increasing concentration of advertising spending, including mobile spending, in a small number of very large competitors;
acts of competitors and other third parties that can adversely affect our business;

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our ability to differentiate our offerings and compete effectively in a market trending increasingly toward commodification, transparency, and disintermediation;
requests from buyers and sellers for discounts, fee concessions or revisions, rebates, refunds and greater levels of pricing transparency and specificity;
potential adverse effects of malicious activity such as fraudulent inventory and malware;
the effects of seasonal trends on our results of operations;
costs associated with defending intellectual property infringement and other claims;
our ability to attract and retain qualified employees and key personnel;
our ability to identify future acquisitions of or investments in complementary companies or technologies and our ability to consummate the acquisitions and integrate such companies or technologies; and
our ability to comply with, and the effect on our business of, evolving legal standards and regulations, particularly concerning data protection and consumer privacy and evolving labor standards.
We discuss many of these risks and additional factors that could cause actual results to differ materially from those anticipated by our forward-looking statements under the headings "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations," and elsewhere in this report and in other filings we have made and will make from time to time with the Securities and Exchange Commission, or SEC, including Quarterly Reports on Form 10-Q for 2018. These forward-looking statements represent our estimates and assumptions only as of the date of the report in which they are included. Unless required by federal securities laws, we assume no obligation to update any of these forward-looking statements, or to update the reasons actual results could differ materially from those anticipated, to reflect circumstances or events that occur after the statements are made. Without limiting the foregoing, any guidance we may provide will generally be given only in connection with quarterly and annual earnings announcements, without interim updates, and we may appear at industry conferences or make other public statements without disclosing material nonpublic information in our possession. Given these uncertainties, investors should not place undue reliance on these forward-looking statements.
Investors should read this Annual Report on Form 10-K and the documents that we reference in this report and have filed or will file with the SEC completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.

PART I
Item 1. Business Overview
We provide a technology solution to automate the purchase and sale of digital advertising inventory for buyers and sellers. Our platform features applications and services for digital advertising inventory sellers, including websites, mobile applications and other digital media properties, to sell their advertising inventory; applications and services for buyers, including advertisers, agencies, agency trading desks, and demand side platforms, or DSPs, to buy advertising inventory; and a marketplace over which such transactions are executed. Together, these features power and enhance a comprehensive, transparent, independent advertising marketplace that brings buyers and sellers together and facilitates intelligent decision-making and automated transaction execution for the advertising inventory we manage on our platform. Our clients include many of the world’s leading publishers of websites and mobile applications and buyers of digital advertising inventory.     
Advertising inventory takes different forms, referred to as advertising units, is purchased and sold through different transactional methodologies, and allows advertising content to be presented to users through different channels. Our solution enables buyers and sellers to purchase and sell:
a comprehensive range of advertising units, including display, audio and video;
that are transacted through real-time bidding ("RTB"), which includes (i) direct sale of premium inventory, which we refer to as private marketplace ("PMP"), and (ii) open auction bidding, which we refer to as open marketplace ("OMP"); and
that are displayed across digital channels, including mobile web, mobile application, and desktop, as well as across various out-of-home channels, such as digital billboards.
We believe our platform reaches approximately one billion users globally. Sellers of digital advertising inventory use our platform to generate revenue by monetizing their advertising inventory across transaction types, advertising units, and channels through accessing a global market of buyers representing top advertiser brands. We also help sellers decrease costs and protect their brands and user experience.

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At the same time, buyers leverage our platform to manage their advertising spending and reach their target audiences across transaction types, advertising units, and channels, simplify order management and campaign tracking, obtain actionable insights into audiences for their advertising, and access impression-level purchasing from hundreds of sellers.
We generate revenue from the buying and selling of advertising inventory transacted on our platform. Advertising inventory is created when users access sellers’ content. Sellers provide advertising inventory to our platform in the form of advertising requests, or ad requests. When we receive ad requests from sellers, we send bid requests to buyers, which enable buyers to bid on sellers’ advertising inventory. Winning bids can create advertising, or paid impressions, for the seller to present to the user. The volume of paid impressions measured as a percentage of ad requests is referred to as fill rate. The price that buyers pay for each thousand paid impressions purchased is measured in units referred to as CPM. We refer to the total volume of spending between buyers and sellers on our platform as advertising spend. We keep a percentage of that advertising spend as a fee, and we pass the rest through to the seller. The fee that we retain from the gross advertising spend on our platform is our revenue. Our fee, measured as a percentage of advertising spend, is referred to as our take rate.    
Our platform incorporates proprietary machine-learning algorithms, sophisticated data processing, robust high-volume analytics capabilities, and a distributed infrastructure. Our solution is constantly improving based on our systems’ ability to process and learn from vast volumes of data in real time.
During the early stages of our business following our incorporation in April 2007, our solution matched sellers’ inventory to appropriate buyers by offering impressions to different buyers in sequence. During 2010, we added RTB capabilities, creating a real-time open-market auction allowing all buyers accessing our platform to compete to purchase all of the advertising inventory that sellers made available to our platform. During 2012, we launched our PMP application, which allows sellers to connect directly with their pre-approved buyers to execute direct sales of previously unsold advertising inventory.
In 2014, we completed the acquisitions of iSocket, Inc. ("iSocket") and Shiny Inc. The iSocket acquisition included a workflow tool that we offered as our Guaranteed Orders product, which we decided to cease offering and supporting in the first quarter of 2018. The Guaranteed Orders tool was a small component of what we historically referred to as our "Orders" platform, which also includes PMPs. The majority of the transactions associated with our Orders platform are PMP transactions and thus are not impacted by this decision to cease offering our Guaranteed Orders tool.
In 2015, we acquired Chango Inc. ("Chango"), an intent marketing technology company, and integrated its operations into our operations. In the first quarter of 2017, we ceased operating the intent marketing solution that had derived from the acquisition.
In 2015, we also significantly advanced our mobile capabilities through a combination of internal product development, strategic client wins, driving increased revenue from existing buyer and seller clients, and international expansion. Part of this growth was due to the development and roll out of our Exchange API (xAPI) solution, which allows us to access inventory from sellers with their own RTB capabilities, as well as large aggregators of inventory.
In 2016, we introduced our header bidding solution, which was late to market but grew rapidly. In addition, we began to focus further on development of our video solution, helping grow our product footprint to allow our sellers to sell video advertising inventory across desktop or mobile platforms, and include instream, outstream and mobile-specific formats such as interstitials.
In 2017, we acquired nToggle, Inc. ("nToggle"), a provider of technology to make it easier and more cost effective for programmatic buyers to find the inventory they are looking for among the billions of bid requests they receive each day. Header bidding has dramatically increased the volume of bid requests sent to buyers, increasing buyers’ processing costs and making it more difficult for them to find the impressions they want. nToggle technology utilizes analytical and data science techniques to help shape real-time bidding requests, optimize traffic, and reduce the number of duplicates and irrelevant bid requests DSPs must process. The technology also helps us manage our infrastructure costs by filtering out impressions that are not in demand before they are processed through the bid stream.
We operate our business on a worldwide basis, with an established operating presence in North America and Europe and a developing presence in Asia, Australia, and South America. Substantially all of our assets are U.S. assets. Our non-U.S. subsidiaries and operations perform primarily sales, marketing, and service functions.
Recent Developments
The ad tech market is demanding more efficiency and lower cost from intermediaries like us. In an effort to be more competitive in attracting demand and capturing inventory supply, we made a strategic decision in mid-2017 to reduce the fees we

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charged buyers in OMP transactions. In addition, in 2017 our business mix shifted to a higher proportion of header bidding transactions, and we charged lower buyer fees for header bidding transactions in order to pass higher bids to the downstream decisioning process. Finally, in response to increasing market pressure and in an effort to be more competitive, on November 1, 2017, we eliminated our buyer transaction fees altogether.
Buyer transaction fees represented approximately 51% of our revenue in 2016 and 49% of our revenue for the first ten months of 2017, which is the period during which we charged buyer fees in 2017. Consequently, the elimination of our buyer transaction fees has had a severe adverse effect on our revenue and margins. A critical part of our plan to adjust to our lower take rates is to increase advertising spending on our platform and operate with improved efficiency that will support lower margins. To increase our advertising spend, we are taking steps to increase significantly the ad requests coming from our seller clients. Our plans for increasing our inventory volumes include active pursuit of more direct relationships with sellers, particularly of mobile, video, and PMP impressions, which are areas of industry growth. We also plan to access ad requests that might not otherwise be accessible to us by utilizing header bidding technologies, including our own solution built on the Prebid open source architecture we helped advance, as well as third-party wrappers, and also integrating with large sources of supply that have their own monetization capabilities but also allow third parties to connect to their exchanges and bid on their inventory.
Historically, OMP transactions, particularly for desktop display advertising, have provided most of the activity on our platform. We expect our historical OMP desktop display advertising business to continue to be an important source of revenue for us, but consistent with market trends, our OMP desktop display business has declined significantly as other transaction types and channels have absorbed a greater share of advertising spend. In addition, our share of the OMP desktop display market has diminished, largely because header bidding has allowed other exchanges to compete more effectively for inventory. Accordingly, our OMP desktop display transactions are declining as a percentage of our business and cannot be relied upon to drive growth. In order for us to grow and compete effectively, we must continue to increase our business in other transaction types, such as PMP transactions, other channels, such as mobile and out-of-home, and other advertising units, such as video, all of which are growth areas in the market; innovate to adapt to changing market conditions; and further increase our international business in existing and new markets.
The industry-wide growth of header bidding has given us access to more advertising inventory, but has also exposed inventory to more competing sources of demand. As a result, we have significantly lower fill rates for header bidding transactions, and as the percentage of our overall transactions conducted through header bidding increases, our overall fill rates decrease. In an effort to increase our header bidding fill rates, in addition to our plans described above, we have made adjustments to our auction dynamics in header bidding transactions. Historically, we conducted our RTB auctions based upon second-price principles, consistent with widespread industry practice. However, as header bidding increased competition for available inventory, some competing exchanges began submitting bids in header bidding auctions on a first-price or modified first-price basis to increase their chances of winning. This put our buyers at a competitive disadvantage in these transactions and also created some confusion in the market, as it was often unclear how competing buyers were formulating their bids. In an effort to capture more inventory for our buyers and deliver better monetization to our sellers, and to provide better transparency and predictability to all our clients, effective as of January 22, 2018, we made first price our default auction dynamic for header bidding transactions. This means that the first price or highest bid in our auction wins and that first price is passed to the downstream auction. Because buyers may need some time to adapt their systems and bidding strategies to first-price auction dynamics, or may not wish to make those adaptations themselves, we have implemented an optional free feature, which we call Estimated Market Rate ("EMR"). This feature uses algorithms that monitor existing market conditions against our dataset of auction outcomes to look for opportunities to reduce the amount of the bid that we pass through to the downstream auction on behalf of our winning bidder, while maintaining high fill rates. This is intended to help buyers bid on advertising inventory consistent with market values while preserving demand and budget for sellers on our platform.
While we work to increase the volume of transactions on our exchange and compete more effectively, we must operate more efficiently to relieve the pressure on our margins and cash resources that has resulted from our fee reductions and increased infrastructure required to support the increased volume of transactions that our growth plans require. Consequently, we are pursuing various cost-control measures and efficiency initiatives. As part of these efforts, during the first quarter of 2018 we undertook measures to reduce headcount by approximately 100 people, or 19% of our workforce, and to reduce other operating costs. Our actions include reductions in administrative staff to bring our general and administrative operations into better alignment with the current size of the business as well as in sales and technical personnel as a result of offshoring certain development functions, organizational delayering and restructuring, and reducing investment in unprofitable projects. These headcount actions have reduced our staff levels from 514 at December 31, 2017 to approximately 415. The reductions will result in approximately $3.0 million in one-time cash severance costs, which will primarily be recognized in the first quarter of 2018. Net of these severance expenses, our workforce reductions combined with other non-headcount related operating expense control initiatives we have implemented, are expected to offset operating expenses in 2018 by approximately $15.0 million. On an annualized basis, the headcount reductions and other cost-control measures we have implemented in the first quarter of 2018 are

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expected to offset future cash expenses by approximately $24.0 million. Including prior headcount actions undertaken in the fourth quarter of 2016 and first quarter of 2017, we have reduced our headcount by over 250 people, or 38% from our September 30, 2016 headcount of 672. We also continue to pursue increased automation and efficiency across all aspects of the company, including our technology stack, and estimate that our capital expenditures in 2018 will be less than half of the $40.4 million in capital expenditures incurred in 2017.
Our growth and cost-control strategies involve significant risk, as described in the “Risk Factors” section of this report.
Our Industry
Continued Shift Toward Digital Advertising
The increased delivery of content to users digitally over the Internet or through applications, as opposed to analog and print media, such as newspapers, magazines, broadcast radio, and television, has created an opportunity for buyers of advertising inventory to improve return on advertising investment by targeting audiences more accurately using data-driven strategies and delivering more relevant advertising in real time on multiple screens. Buyers are able to utilize various technologies to analyze data relating to return on investment, demographics, user behavior, location, and other attributes that enable them to create and deliver targeted advertisements to users, which helps achieve specific advertising goals. Technological advances have also enabled sellers to sell their inventory on an impression-by-impression basis, as well as in bulk, making it easier for sellers to enhance the monetization of their inventory. Therefore, advertising is continuing to shift with content to digital media.
Complicated and Manual Workflow for Direct Buying and Selling of Digital Advertising Inventory
Due to the size and complexity of the advertising ecosystem and purchasing process, manual processes cannot effectively manage digital advertising inventory at scale. In addition, both buyers and sellers are demanding more transparency, better controls and more relevant insights from their advertising inventory purchases and sales. Buyers and sellers benefit from a platform that enables them to leverage the targeting capabilities of their proprietary data assets. This has created a need to automate the digital advertising industry and to simplify the process of buying and selling advertising inventory.
A variety of factors make the digital advertising ecosystem highly complex and challenging to automate:
Perishable Inventory. A user’s visit to a website or mobile application creates a unique opportunity to reach the user by inserting advertisements into one or more of the impressions designed into the website or mobile application. In order to generate revenue for a seller these impressions must be filled before the page content loads.
Complex Impression-Level Matching. Sellers aim to sell impressions in order to generate revenue while enhancing the users’ experience and preserving the sellers’ brand. Buyers seek to purchase impression-level inventory to improve targeting of specific audiences and return on investment for their advertising spending.
Large Multi-Variate Datasets. Trillions of data points relating to browsing behavior, geographic information, user preferences, engagement with an advertisement, and effectiveness of an advertisement are created as users visit sellers’ websites and mobile applications. Each piece of data represents a valuable piece of information that can facilitate and improve current and subsequent targeting and monetization of impressions.
Fragmented Buyer and Seller Base. There is an enormous number and variety of buyers and sellers of digital advertising.
Brand Safety and Inventory Quality Concerns. Buyers want to avoid buying fraudulent or unauthorized inventory or being associated with content they consider inappropriate, competitive, or inconsistent with their advertising themes. Sellers want to prevent advertisements that are inappropriate, disruptive, competitively sensitive, or otherwise do not comport with their brand image from appearing on their websites or mobile applications, or that convey malware.
Consumer Experience Concerns. Consumers prefer digital advertising experiences that are relevant to their personal interests, non-intrusive, and do not detract from or slow down their enjoyment of digital content.

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Large and Highly Unpredictable Traffic Volumes. The scale of user traffic and the dollar value of digital advertisements is growing and difficult to manage efficiently. A large seller may have tens of millions of users per month, creating hundreds of millions of monthly impressions. The volume of traffic for any given seller is extremely difficult to predict and requires a technology infrastructure that is large enough to handle variable volumes. As more advertising shifts to digital and digital advertising technologies evolve, larger and more diverse data processing capabilities are required.
Lack of Standardized Ad Formats and Data. An available advertising impression can vary based on a number of factors, such as seller, ad format, screen size, pricing mechanism, content type, and audience demographic. It is challenging for buyers to efficiently evaluate and bid on trillions of impressions that are based on hundreds of ad formats in the context of millions of highly customized data fields.
Diverse Technology Demands. Even as advertising is shifting from traditional to digital media, a shift is underway within the digital advertising ecosystem from desktop to mobile channels. Desktop and mobile digital advertising involve different challenges and rely upon different technologies, requiring significant technological capabilities and innovation.
Increasing Privacy Demands. Privacy protection is becoming increasingly important to regulators, web and mobile browser applications and users on a regional and global basis, requiring constant adaptation to comply with legal and self-regulatory requirements while effectively matching buyers and sellers of inventory.
Rubicon Project: Competitive Strengths of Our Platform in the Digital Advertising Marketplace
Rubicon Project was founded to address the inherent challenges associated with the digital advertising ecosystem. Buyers can direct their spending towards the impressions that are of most value to them based on demographics, pricing, timing, and other targeting objectives. Sellers can improve revenue per impression, while adhering to their own specific rules around advertising that is permissible on their websites and mobile applications.
Serving a Broad Universe of Buyers and Sellers Across a Full Spectrum of Inventory Types, Advertising Units, and Channels Creates Network Effects
By accommodating a full spectrum of digital advertising inventory through various transaction types across multiple channels, our solution brings value to both buyers and sellers. Our sellers gain instant access to the world’s largest automated digital advertising buyers, including hundreds of DSPs with the flexibility to sell their advertising inventory in an automated fashion on an impression-by-impression basis, such as with OMP, in bulk, or in PMP transactions pursuant to arrangements directly between the seller and the buyer. Our buyers gain the ability to fulfill their audience needs in a cost-effective manner and while increasing the price at which sellers’ inventory is sold. Large numbers of diverse sellers on our platform attract more buyers and vice versa, resulting in a self-reinforcing network effect that adds value for all our clients and creates a strong platform for growth.
Private Marketplace Solutions Provide Unique Access to Quality Supply and Facilitate Transactions
A significant portion of premium inventory is purchased and sold through PMPs. Some sellers will continue to rely on their own sales forces for sales of premium inventory, but will benefit from automation to better price, match, and place campaigns, and to automate manual operations such as ad trafficking, quality assurance, and billing and collections. We have invested in workflow capabilities and automation of inventory transactions to enable sales teams to increase their productivity and process more sales of premium inventory at optimal prices. Workflow capabilities enable buyers and sellers to communicate directly and use shared data to execute campaigns. These capabilities support sales functions rather than replacing them, enhancing their adoption without friction. Buyers and sellers can also leverage their first-party data assets and third-party data assets in our platform to increase the value of sellers' inventory and the precision of buyers' targeting efforts.
Big Data Analytics and Machine-Learning Algorithms
A core aspect of our value proposition is our big data and machine-learning platform that is able to discover unique insights from our massive data repositories containing proprietary information on trillions of bid requests and served advertisements. Our systems collect and analyze non-personally identifiable information such as pricing of advertisements, historical clearing prices, bid responses, what types of ads are allowed on a particular website, which sellers’ websites a buyer prefers, what ad formats are available to be served, advertisement size and location, user location, which users a buyer wants to target, how many ads the user has seen, browser or device information, and sellers’ proprietary data about users. Our access to data puts us in a unique position to develop differentiated insights to help both buyers and sellers, and we have developed proprietary machine-learning algorithms that analyze billions of these data points to enable our solution to make data-driven

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decisions in real time and to process high volumes of bid requests and responses. Our solution is constantly self-improving as we process more volume and accumulate more data, which in turn helps make our machine-learning algorithms more intelligent and contributes to higher-quality matching between buyers and sellers. Higher quality matching improves return on investment for buyers and increases revenue for sellers, which in turn attracts more buyers and sellers to our platform. We believe this self-reinforcing dynamic contributes to the dual network effects described above, creating a strong platform for growth.
Header Bidding Solution
Header bidding is effectively a change in the auction process by which, instead of allocating an impression to one exchange running a single auction, a publisher exposes the impression to multiple exchanges, each of which selects a winning bid through its own initial auction and passes that winning bid into a secondary auction to compete for the impression with all other participating exchanges’ winning bids. Sellers first embraced header bidding using a client-side solution, in which the browser of the user creating the impression runs the secondary auction. This solution increases competition for impressions and raises impression prices, but burdening the browser to perform the secondary auction increases load time for content and time delays during execution.
An emerging alternative header bidding protocol uses a server to conduct the secondary auction, which can reduce load times but presents its own challenges. Adding an additional step between the user’s browser and the demand source can cause increased latency and limit the amount of user data that is transmitted, contributing to difficulties in user data synchronizing and resulting in adverse effects on audience targeting. Server-side technology also significantly increases the volume of demand sources that can be accommodated, resulting in increased competition for impressions. Further, the host of the server used in a particular transaction has an advantage in user synch with its demand sources, at least until some form of universal user identification approach gains significant market adoption.
In 2016, we entered the client-side header bidding space with our client-side solution, FastLane, which was late to market but grew rapidly in adoption. In 2017, we began working on server-side header bidding and supported an open source industry solution we helped advance called Prebid. In October 2017, we launched our own open source server-side header bidding solution, which integrates with Prebid. Using these technologies, we are executing header bidding secondary auctions on behalf of our seller clients that implement our solution. To further the open source initiative, in 2017 we also helped to launch Prebid.org, Inc., an independent organization dedicated to the development and promotion of open-source header bidding solutions and other open-source tools to drive publisher monetization. There are two other primary server-side solutions, one provided by Amazon (called A9) and one provided by Google (called EBDA), and we are integrated with both. We believe the various header bidding alternatives we offer, our buyer reach and scale, our buying efficiency, and our machine learning capabilities put us in a strong position to compete for seller impressions, and we expect each of these header bidding solutions to deliver a meaningful volume of impressions in 2018 and beyond.
Independence
Unlike some large industry participants, we do not have our own media properties that compete for advertising spending with our sellers. Our independence means we have none of the inherent conflicts of interests characterizing competing exchanges that sell their own inventory, giving our clients an important alternative to monetize and acquire inventory without subsidizing their competitors.
Platform Applications
To enhance the value our technology platform brings to the marketplace, we offer a number of applications to address the critical needs of buyers and sellers.
Applications for Sellers. We have direct relationships and integrations with the sellers on our platform. Our solution includes applications to help them increase their digital advertising revenue, reduce costs, protect their brands and user experience, and reach more buyers efficiently to increase digital advertising revenue by monetizing their full variety and volume of inventory. Our platform offers sellers many capabilities and benefits, including the following:
xAPI Technology That Allows Sellers to Easily Access Our Demand. Publishers normally face numerous technical challenges in accessing advertising demand. They either have to modify their web pages by adding cumbersome "ad tags," or they have to integrate monetization code into their mobile applications. Both of these methods create technical risk and are time consuming to implement. xAPI technology eliminates these requirements and makes it easy and fast with no impact to the web pages or apps of the publisher to access demand and fill ad slots.

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Integrated Solution for Digital Advertising Needs. We provide sellers with a single web-based interface that serves as their central location to manage, analyze, and enhance digital advertising spending from hundreds of different buyers.
Header Bidding. We provide our own header bidding solutions to sellers to use as a platform for aggregating demand, and also to integrate with third-party header bidding solutions to provide demand to our sellers that use those third-party solutions as their header bidding platform.
Private Marketplaces. Sellers can use our PMP capabilities to augment their own internal sales operations through better matching and pricing and process automation.
Inventory Allocation. We offer a solution that helps sellers to increase revenue across advertising types and sales channels by allocating inventory efficiently between direct and indirect demand.
Significantly Streamlined Sales, Operations, and Finance Workflow. Our platform streamlines the management of digital advertisement sales by aggregating demand and providing a suite of software applications that automate the process of making inventory available for sale.
Security for Brand and User Experience. Our platform is designed to enable sellers to implement guidelines specifying what advertising content may not be shown on the seller’s website or mobile application.
Advanced Reporting and Analytics and Actionable Insights. We provide a robust set of reporting features that sellers can use to analyze the vast array of data we collect for them.
Consolidated Payments. We provide consolidated billing and collection for sellers that would otherwise be required to dedicate additional resources to cost-effectively manage financial relationships with a large base of buyers.
Protective Screening. We employ measures to protect sellers and users from malware (software that can infect computers with malicious software), check advertisements delivered through our solution for the presence of malicious or questionable activity or characteristics, and gather technical attributes to inform our matchmaking process.
Vantage. We provide an extension for Web browsers that lets sellers monitor ads served in context on their sites, providing insight, diagnostic applications, and ad-quality controls.
Creative Approval API. Our platform includes a programmatic interface that sellers can use to retrieve a comprehensive set of individual advertising creatives that have bid or served on their sites, and instruct our delivery systems to approve or reject those creatives for future impressions.
Applications for Buyers. Buyers leverage our applications to access a large audience and execute highly automated campaigns that take advantage of unique targeting data and technology as provided by our platform to purchase advertising inventory based on buyers' key demographic, economic, and timing criteria. These applications help streamline a buyer’s purchasing operations and increase the efficiency of its spending and the effectiveness of its advertising campaigns. Our platform offers buyers many capabilities and benefits, including the following:
Direct Access to a Global Audience and Hundreds of Premium Sellers. By leveraging our platform, we believe buyers can reach approximately one billion internet users globally, including through many of the world's largest and most premium sellers. Furthermore, unlike many organizations in the digital advertising industry, we have direct relationships with sellers and can enable buyers to circumvent a multi-step, expensive, and inefficient process to connect to the seller.
Private Marketplaces. Through our PMP capabilities, we enable buyers to access exclusive high-value inventory in a more controlled environment than in the open marketplace.
Bid Stream Filtering. We provide technology to help buyers shape real-time bidding requests, optimize traffic, and reduce the number of duplicates and irrelevant or undesired bid requests they must process. This helps buyers find the inventory they are looking for more efficiently and reduces their data processing costs.
Bid Reduction. Buyers participating in header bidding auctions, which we conduct on a first-price basis, may use our EMR technology, which uses our market data and proprietary algorithms to help buyers bid on advertising inventory consistent with market rates.
Flexible Access to Inventory. Our platform allows buyers to purchase advertising inventory in their preferred manner, whether by OMP or PMP. Our solution also has the flexibility to allow buyers to integrate their purchases on our platform through their existing buying technologies or to buy directly through our platform.

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Simplified Order Management and Campaign Tracking. By eliminating most manual steps, our applications enable buyers to manage their digital campaigns efficiently and effectively, and significantly reduce the time it would otherwise take to execute their digital advertising programs.
Transparency and Control Over Advertising Spending. Our platform is designed to let buyers know and control where their dollars are being spent. Buyers can easily navigate through our interface to choose the list of sellers they want to purchase inventory from and see an indicative price range that they should expect to pay.
Inventory Quality. We provide systems and processes to detect and minimize questionable inventory, such as non-human traffic and pirated content, and to enable labeling of inventory made available for sale so that buyers can make their own decisions about what meets the specific standards of campaigns they are running.
PubCheq. We maintain a comprehensive database of all inventory reviewed by internal systems and teams that powers a global blacklist that blocks fraudulent or otherwise problematic seller properties and users from entering the Rubicon Project marketplace and identifies non-human traffic that is fraudulently consuming advertising spend.
Growth Strategies
Two powerful market trends are affecting our business. First, our exchange volume historically consisted largely of OMP transactions conducted through an ad server waterfall for desktop display advertising, but this business is being displaced by other ad units, channels, and transaction types. Second, the ad tech market is demanding more efficiency and lower cost from intermediaries like us, and we believe market share will consolidate. Our strategy for growth in this context is to operate a high-volume, low cost per transaction exchange, and focus on high-growth ad units, channels and transaction types.
Increase volumes and efficiencies and reduce transaction costs on our exchange. We aim to increase our transaction volumes and to enhance the operational efficiency and value to clients of our exchange, enabling buyers and sellers to achieve their campaign and monetization objectives efficiently and to streamline the number of exchanges they work with.
Increasing Inventory Supply. Increased transaction volume begins with ad requests from sellers, which represent the inventory available for buyers to purchase on our platform. Our plan for increasing our inventory volumes includes active pursuit of more direct relationships with sellers, particularly of mobile, video, and PMP impressions, which are areas of industry growth. Our own header bidding solutions are an important element of our offering to large sellers. We also plan to access ad requests that might not otherwise be accessible to us by connecting to third-party header bidding solutions such as Google’s EBDA and Amazon’s A9, as well as other third-party wrappers, and also integrating through our server-to-server xAPI technology with large sources of supply that have their own monetization capabilities but also allow third parties to connect to their exchanges and bid on their inventory.
Elimination of Buyer Fees. During 2017, we reduced and ultimately eliminated the transaction fees we previously charged buyers for OMP transactions. As a result, our total take rate was approximately 11.6% as we exited 2017, which did not include any buyer fees. We believe our pricing is now extremely competitive, and our low take rate is intended to address the market's demand for lower costs and to attract more inventory and spending to our platform. Elimination of buyer fees also allows us to pass higher bids to the downstream auction in header bidding transactions, which should improve our fill rate. In addition, elimination of our buyer fees, as well as the auction dynamics and bid filtering described immediately below, reflect our intensified focus on buyers, which, through “supply path optimization” initiatives, are expected to concentrate their spending to fewer more efficient sources of advertising inventory.
More Competitive Auction Dynamics. Increased competition inherent in header bidding led other exchanges to submit bids on a first-price basis, rendering our second-price auction methodology less competitive. Therefore, effective as of January 22, 2018, we made first-price our default auction dynamic for header bidding transactions. We expect this to improve the rate at which we win header-bidding auctions. To support buyers that need some time to adapt their systems and bidding strategies to first-price auction dynamics, or may not wish to make those adaptations themselves, we provide our EMR feature.
Bid Filtering. Our plans to improve our fill rate include using the technology we acquired from nToggle to filter out low-quality impressions so that a higher proportion of the ad requests on our platform are of interest to our buyers, and to enable our buyers to identify and purchase the impressions they want more efficiently. In addition, we expect the nToggle filtering technology to help us and our buyers control the processing costs associated with higher volumes of ad requests and bid requests.

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Platform Enhancements. We are working on a number of platform innovations and enhancements designed to improve the value to clients and the operational efficiency of our platform. For example, new technology and techniques will improve upon our market-leading position in inventory and ad quality, responding to market demands for increased brand security and protection against fraud. Cookie-less targeting, including device-based user identifiers, will improve audience identification and match rates. Audience-based selling and enhanced measurement and viewability technologies will improve inventory values for sellers and campaign effectiveness for buyers. Impression filtering and virtual machine support will improve the efficiency and effective capacity of our data processing infrastructure.
Focus on emerging ad units, channels, and transaction types
Our business historically consisted largely of OMP transactions conducted through an ad server waterfall for desktop display advertising. This business, while still an important source of revenue for us, is contracting. In order for us to grow and compete effectively, we must continue to focus on areas of the digital advertising business that are experiencing growth and to adapt to evolution in the business.
Mobile: We believe we can significantly expand the penetration of our mobile offerings among buyer and seller clients by creating and introducing new mobile ad formats, growing mobile advertising by brands with better measurement and decisioning data, and leveraging header bidding to improve returns for developers. Mobile includes mobile web pages as well as mobile applications.
Audiences: We aim to develop technology to enable buyers and sellers to safely leverage their first-party data assets and third-party data assets in our platform to increase the value of sellers' inventory and the precision of buyers' targeting efforts, and to drive more precise matching of buyer demand to seller inventory. As the world continues to move more toward an app-centric consumption of the Internet, our concept of identity is evolving away from the browser cookie and into more sophisticated ID-agnostic systems and technology.
Header Bidding: We will invest in continued improvement in our header bidding capabilities, including through support of open-source wrapper technologies that eliminate exchange bias as well as expand support for major third-party header bidding technologies and additional formats to maximize access to inventory supply, and development of enhanced customer service capabilities.
Private Marketplace: We will continue to invest in our PMP solution, which we believe is well-positioned to take advantage of increased industry demand for PMP transactions.
Video. We plan to expand our video presence by continuing to drive growth with header bidding, new formats and stronger measurement and targeting capabilities, and providing monetization service for over-the-top ("OTT") and connected television content providers as they migrate increasingly to programmatic monetization of their advertising inventory.
Bringing Automation to Additional Media. Historically, our solution has focused on display advertising. We believe, however, that television and other analog and print media will eventually converge with existing digital channels, creating opportunities for us to expand our solution beyond digital media to analog and print media, such as television, radio, and magazines, as well as further expand in out-of-home media like billboards. We intend to extend our solution to track this convergence and support increasingly complex volumes of advertisements spanning multiple media. In addition to platform expansion, we intend to extend beyond our current capabilities for display, video, and engagement to other forms of advertising units as they may arise.
Technology and Development
To support our solution, we have developed globally distributed infrastructure hosted at data centers in the U.S., Europe, and Asia that run our proprietary software and process privacy-enabled user data, including analytics and decision-making algorithms, and store, manage, and process rules set by buyers and sellers and data about demographics, economics, timing, and preferences. Our hardware provides significant scale and is programmed for high-frequency, low-latency transactions. Its massive scale supports the volume, diversity, and complexity of buyers’ bids on sellers’ advertising inventory to increase market liquidity, and it achieves improved auction pricing using our machine-learning algorithms. This infrastructure is supported by a real-time data pipeline, a system that quickly moves volumes of data generated by our business into reporting systems that allow usage both internally and by buyers and sellers. It also is supported by a 24-hour Network Operations Center, which provides failure protection by monitoring and rerouting traffic in the event of equipment failure or network performance issues between buyers and our marketplace.

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Auction and security algorithms use matchmaking algorithms with both historical and real-time data to drive automated decision-making processes. Bid efficiency algorithms provide bid prediction (i.e., which buyers are most likely to bid on a given impression) and throttling (i.e., the volume of bid requests a given buyer can process), to improve infrastructure load and execute transactions in the most timely manner possible by only sending bid requests to those buyers of advertising inventory who can handle the volume and are likely to respond.    
Our core technology and development team is responsible for the design, development, operation, and maintenance of our platform. Our technology and development process is based on agile development methodologies and emphasizes frequent, iterative, and incremental development cycles. Within the technology and development team, we have several highly aligned, independent sub-teams that focus on particular features of our platform. Each of these sub-teams includes engineers, quality assurance specialists, and product developers responsible for the initial and ongoing development of each sub-team’s feature. In addition, the technology and development team includes our technical operations sub-team, which is responsible for the performance and capacity of our platform. While our sub-teams operate independently, the combined work is coordinated by our project management team, which manages dependencies and optimizes the schedule of the entire team towards common goals.
Technology and development expenses are composed of both cost of revenue (excluding amounts paid to sellers for transactions reported on a gross revenue basis) and technology and development on our consolidated statements of operations. These combined expenses, excluding amounts associated with intangible asset write-offs, were $103.7 million, $102.3 million and $79.4 million for the years ended December 31, 2017, 2016 and 2015, respectively.
We believe that continued investment in our platform, including its technologies and functionalities, is critical to our success and long-term growth. We therefore expect technology and development expenses to increase as we continue to invest in technology infrastructure to support an increased volume of advertising spending on our platform and international expansion, as well as to expand our engineering and technology teams to maintain and support our technology and development efforts. We also intend to invest in new and enhanced technologies and functionalities to enhance our platform and further automate our business processes with the goal of enhancing our future profitability.
Sales and Marketing
We market our solution to buyers and sellers through global direct sales teams that operate from various locations around the world. These teams leverage market knowledge and expertise to demonstrate the benefits of advertising automation and our solution to buyers and sellers. We deploy a professional services team with each seller integration to assist sellers in extracting value from our solution. Our buyer team focuses on the unique challenges and priorities of buyers and is separately managed in order to properly represent this important client group. We are focused on managing our brand, increasing market awareness, and driving advertising spend to our platform. To do so, we often present at industry conferences, create custom events, and invest in public relations. In addition, our marketing team advertises online, in print, and in other forms of media, creates case studies, sponsors research, writes whitepapers, publishes marketing collateral, generates blog posts, and undertakes client research studies.
Competition
Our industry is highly competitive. Overall digital advertising spending is highly concentrated in a small number of very large companies that have their own inventory, including Google and Facebook, with which we compete for digital advertising inventory and demand. These companies are formidable competitors due to their huge resources and direct user relationships. Despite the dominance of large companies, there is still a large addressable market that is highly fragmented and includes many providers of transaction services with which we compete, including supply side platforms, or SSPs, and advertising exchanges. As we introduce new offerings, as our existing offerings evolve, or as other companies introduce new products and services, we may be subject to additional competition. There has been rapid evolution and consolidation in the advertising technology industry, and we expect these trends to continue, thereby increasing the capabilities and competitive posture of larger companies, particularly those that are already dominant in various ways, and enabling new or stronger competitors to emerge. There are many ways for buyers and sellers of digital advertising inventory to connect and transact, including directly and through many other exchanges, and advertising inventory buyers are increasingly demanding more transparency and lower transaction costs and establishing relationships directed with sellers of advertising inventory, which puts significant pressure on us. Our offering must remain competitive in terms of scope, ease of use, scalability, speed, price, inventory quality, brand security, customer service, and other technological features that help sellers monetize their inventory and buyers increase the return on their advertising investment.
While our industry is evolving rapidly and becoming increasingly competitive, we believe that our solution enables us to compete favorably on the factors described above. However, competitive differentiation is difficult to achieve, both in terms of capabilities and in terms of client perception. We lack the scale of some of our competitors, which may have the ability to compete effectively with us by offering broader capabilities or more aggressive pricing. Other competitors with capabilities

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inferior to ours may nevertheless compete effectively with us if clients do not perceive, or value, what we believe to be our competitive advantages.
To an increasing degree, SSPs and exchanges are becoming somewhat similar and less distinguishable in the services that they provide, and with the proliferation of header bidding, which increased competition for impressions, pricing has become a key competitive factor. In 2017, we continued to see a heightened level of competition on pricing sensitivity, which led us to implement buyer fee reductions in the first half of the year and ultimately to eliminate all our buy side transaction fees on November 1, 2017. As a result, our overall take rate in 2017 dropped to 18.5% as compared to 25.0% in the full year 2016 and exited 2017 at approximately 11.6%. We believe this take rate puts us in a favorable competitive position in terms of pricing, but it is uncertain whether it represents a sustainable competitive advantage or if we can increase our transaction volume enough to compensate for lower prices.
Our Team and Culture
Our team consists of ad tech pioneers and veterans that draw from a broad spectrum of experience, including data science, artificial intelligence, machine-learning algorithms, auctions, infrastructure, and software development.
We focus heavily upon developing and maintaining a company culture that supports our goals. We strive to make our company an exciting place to work, not just a “job.” We reward team and individual excellence and constantly strive to build a stronger, more innovative team and a consistent culture across all our locations.
As of December 31, 2017, we had 514 full-time employees, of whom 198 were in sales and marketing functions, 209 were in technology and development, and 107 were in general and administrative functions. There were 408 full-time employees located in the United States. In addition to the United States, we had 106 personnel and operations in England, Canada, France, Australia, Germany, Italy, Japan, Singapore, Brazil, and the Netherlands. As of March 14, 2018, and giving effect for the reductions in force described in “Business Overview - Recent Developments,” we would have approximately 415 full-time employees.
Our Intellectual Property
Our proprietary technologies are important and we rely upon trade secret, trademark, copyright, and patent laws in the United States and abroad to establish and protect our intellectual property and protect our proprietary technologies.
We have nine issued U.S. patents, as described below. Additionally, we have six pending patent applications in the United States and two pending non-U.S. patent applications, some of which may ultimately go abandoned if we determine that the cost of prosecution does not justify the utility of receiving the patent. None of these patents has been litigated and we are not licensing any of the patents. Their importance to our business is uncertain and there are no guarantees that any of the patents will serve as protection for our technology or market in the United States or any other country in which an application has been filed. Our nine issued U.S. patents include: U.S. Patent No. 11,959,385, titled Auction for Each Individual Ad Impression, issued on February 6, 2018; U.S. Patent No. 9,898,762, titled Managing Bids in a Real-Time Auction for Advertisements, issued on February 1, 2018; U.S. Patent No. 8,472,728, titled System and Method for Identifying and Characterizing Content within Electronic Files Using Example Sets, issued on June 25, 2013; U.S. Patent No. 8,473,346, titled Ad Network Optimization System and Method Thereof, issued on June 25, 2013; U.S. Patent No. 8,554,683, titled Content Security for Real-Time Bidding, issued on October 8, 2013; U.S. Patent No. 8,831,987, titled Managing Bids in a Real-Time Auction for Advertisements, issued on September 9, 2014; U.S. Patent No. 9,076,151, titled Graphical Certifications of Online Advertisements Intended to Impact Click-Through Rates, issued on July 7, 2015; U.S. Patent No. 9,202,248, titled Ad Matching System and Method Thereof, issued on December 1, 2015; and U.S. Patent No. 9,208,507, titled Ad Network Optimization System and Method, issued on December 8, 2015.
We register certain domain names, trademarks and service marks in the United States and in certain locations outside the United States. We also rely upon common law protection for certain trademarks. We generally enter into confidentiality and invention assignment agreements with our employees and contractors, and confidentiality agreements with parties with whom we conduct business, in order to limit access to, and disclosure and use of, our proprietary information. We also use measures designed to control access to our technology and proprietary information. We view our trade secrets and know-how as a significant component of our intellectual property assets, which we believe differentiate us from our competitors.
Any impairment of our intellectual property rights, or any unauthorized disclosure or use of our intellectual property or technology, could harm our business, our ability to compete and our operating results.

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Client Dynamics
While we serve many clients, certain buyers and sellers account for a large share of business transacted through our platform.
On the buy-side of our business, while demand for advertising inventory is diffuse, spending by advertisers on digital advertising inventory has historically been channeled through intermediaries, including principally advertising agencies and DSPs, both of which are important to us. We have generated a majority of our revenue through OMP, and most OMP inventory purchases are executed by a relatively small number of DSPs that have the bidding technologies, data assets, and client bases necessary to enable them to execute OMP purchases at scale on behalf of their clients. We have relationships with almost all of these major DSPs, but because there are relatively few of them, each of these relationships is important to us because it represents a source of demand that could be difficult for us to replace. Similarly, the majority of spending to date on our PMP product has been by a relatively small number of advertising agencies. Creating new agency relationships and expanding our business with existing agency clients is important to our growth, and the loss of any agency clients could adversely affect our PMP business. In addition, because large agencies often spend through multiple DSPs, new or enhanced agency relationships can result in increased spending on our platform by multiple DSPs, while a decrease in business or a decline in our relationship with a single agency can result in reduced spending by multiple DSPs. We are working to develop relationships directly with advertisers, both to provide them with direct access to advertising inventory to supplement their DSP and agency relationships, and also to encourage them to influence their DSPs and agencies to route their spending through our platform.
On the sell-side of our business, while we work with many clients, a relatively small number of them provide a large share of the unique user audiences accessible by buyers. In addition, most of the application providers that make inventory available through our platform utilize system development kits ("SDKs") and other proprietary technology of third parties, such as aggregators, and it is those third parties, not the application providers themselves, that contract with us to help monetize the inventory. Termination or diminution of our relationships with these third parties could result in a material reduction of the amount of mobile inventory available through our platform. We encourage application developers to use our own SDK, but it is difficult to displace existing SDKs.
Our contracts with buyers and sellers generally do not provide for any minimum volumes and may be terminated on relatively short notice. Buyer and seller needs and plans can change quickly, and buyers and sellers are free to terminate their arrangements with us or direct their spending and inventory to competing sources of inventory and demand, quickly and without penalty. Loss of a major buyer could result in a decrease of demand on our platform, and loss of a major seller could result in decrease of inventory available on our platform. Despite such losses, there could still be adequate demand and inventory supply on our platform to sustain and grow our revenue, so it is not necessarily the case that loss of a buyer or seller equates to loss of revenue. However, loss of unique inventory or demand could result directly in revenue loss. In addition, just as growth in the inventory strengthens buyer activity in a network effect, loss of substantial inventory or demand could degrade our marketplace. Loss of major DSP sources of demand could adversely affect bid density or pricing in our RTB auctions, and reduction in fees if we are not able to redirect inventory to other demand sources. Loss of important unique inventory could reduce fees from demand that cannot be shifted to other sellers. The number of large media buyers and sellers in the market is finite, and it could be difficult for us to replace the losses from any buyers or sellers whose relationships with us diminish or terminate.
Because of these factors, we seek to expand and diversify our client relationships. In particular, as part of our strategy to increase the volume of advertising inventory on our exchange, we are initiating relationships with aggregators of inventory and with large sources of supply that have their own monetization capabilities but also allow third parties to connect to their exchanges and bid on their inventory. These relationships represent additional risks in terms of inventory quality, transaction discrepancies, and collections, and may be less profitable because we may be required to compensate these partners or share the fees available for intermediaries in these transactions, and may incur higher serving costs relative to revenue.
Geographic Scope of Our Operations
In addition to the United States, we have personnel and operations in England, Canada, France, Australia, Germany, Italy, Japan, Singapore, Brazil, and the Netherlands. As of December 31, 2017, 106 of our 514 employees were based outside the United States.
Our international operations and expansion plans expose us to various risks. International operations require significant investment in developing the technology infrastructure necessary to deliver our solution and establishing sales, delivery, support, and administrative capabilities in the countries where we operate. We face staffing challenges, including difficulty in recruiting, retaining, and managing a diverse and distributed workforce across time zones, cultures, and languages. We must also adapt our practices to satisfy local requirements and standards (including differing privacy requirements that are sometimes more stringent than in the U.S.), and manage the effects of global and regional recessions and economic and political instability. Transactions

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denominated in various non-U.S. currencies expose us to potentially unfavorable changes in exchange rates and added transaction costs. Foreign operations expose us to potentially adverse tax consequences in the United States and abroad and costs and restrictions affecting the repatriation of funds to the United States.
In the years ended December 31, 2017, 2016, and 2015, approximately 39%, 34%, and 31%, respectively, of our revenue was generated from international markets. A majority of our assets are U.S. assets. For detailed information regarding our revenues and property and equipment, net by geographical region, see Note 16 of the "Notes to our Consolidated Financial Statements."
User Reach
It is not practicable to determine the exact number of unique users we reach because we do not collect personally identifiable information. In order to estimate our user reach, we start with data we track on devices we see through our platform in a given time period: for web browsers, we identify each combination of browser user agent and originating IP address, and for mobile application users, we identify unique device identifiers. The resulting aggregated total counts some devices more than once because the same device creates different user agent and IP address combinations by using different browsers to access the Internet and/or accessing the Internet from locations with different IP addresses. We therefore make assumptions about the amount of duplication, as well as assumptions about the average numbers of devices per person, which can vary by geography and over time, and apply these assumptions to estimate of the number of users we reach. Following this methodology, we estimate that we reach approximately one billion users globally through our platform. This figure depends upon our assumptions and is therefore inherently imprecise and may differ from third-party estimates of our reach.
Regulation
Interest-based advertising, or the use of data to draw inferences about a user’s interests and deliver relevant advertising to that user, has come under increasing scrutiny by legislative, regulatory, and self-regulatory bodies in the United States and abroad that focus on consumer protection or data privacy. In particular, this scrutiny has focused on the use of cookies and other technology to collect or aggregate information about Internet users’ online browsing activity. Because we, and our clients, rely upon large volumes of such data collected primarily through cookies, it is essential that we monitor developments in this area domestically and globally, and engage in responsible privacy practices, including providing consumers with notice of the types of data we collect and how we use that data to provide our services.
We provide this notice through our privacy policy, which can be found on our website at http://www.rubiconproject.com/privacy. As stated in our privacy policy, our technology platform does not collect information, such as name, address, or phone number, that can be used directly to identify a real person, and we take steps not to collect and store such personally identifiable information from any source. Instead, we rely on IP addresses, geo-location information, and persistent identifiers about Internet users and do not attempt to associate this data with other data that can be used to identify real people. This type of information is considered personal data in some jurisdictions or otherwise may be the subject of future legislation or regulation. The definition of personal data varies by country, and continues to evolve in ways that may require us to adapt our practices to avoid violating laws or regulations related to the collection, storage, and use of consumer data. For example, some European countries consider IP addresses or unique device identifiers to be personal data subject to heightened legal and regulatory requirements. As a result, our technology platform and business practices must be assessed regularly in each country in which we do business.
There are also a number of specific laws and regulations governing the collection and use of certain types of consumer data relevant to our business. For example, the Children’s Online Privacy Protection Act ("COPPA"), imposes restrictions on the collection and use of data about users of child-directed websites. To comply with COPPA, we have taken various steps to implement a system that: (i) flags seller-identified child-directed sites to buyers, (ii) limits advertisers’ ability to serve interest-based advertisements, (iii) helps limit the types of information that our advertisers have access to when placing advertisements on child-directed sites, and (iv) limits the data that we collect and use on such child-directed sites.
The use and transfer of personal data in EU member states is currently governed under the EU Data Protection Directive, which generally prohibits the transfer of personal data of EU subjects outside of the EU, unless the party exporting the data from the EU implements a compliance mechanism designed to ensure that the receiving party will adequately protect such data. We have relied on alternative compliance measures, which are complex, which may be subject to legal challenge, and which directly subject us to regulatory enforcement by data protection authorities located in the European Union. By relying on these alternative compliance measures, we risk becoming the subject of regulatory investigations in any of the individual jurisdictions in which we operate. Each such investigation could cost us significant time and resources, and could potentially result in fines, criminal prosecution, or other penalties. Further, some of these alternative compliance measures are facing legal challenges, which, if successful, could invalidate the alternative compliance measures that we currently rely on. It may take us significant time, resources, and effort to restructure our business and/or rely on another legally sufficient compliance measure. In addition, the

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European Union has finalized the General Data Protection Regulation ("GDPR"), which will become effective in May 2018. The GDPR sets out higher potential liabilities for certain data protection violations, as well as a greater compliance burden for us in the course of delivering our solution in Europe; among other requirements, the GDPR obligates companies that process large amounts of personal data about EU residents to implement a number of formal processes and policies reviewing and documenting the privacy implications of the development, acquisition, or use of all new products, technologies, or types of data. Further, the European Union is expected to replace the EU Cookie Directive governing the use of technologies to collect consumer information with the ePrivacy Regulation. Current drafts of the ePrivacy Regulation propose burdensome requirements around obtaining consent, and impose fines for violations that are materially higher than those imposed under the Cookie Directive.
The UK's decision to leave the European Union may add cost and complexity to our compliance efforts. The UK is an important geography for us and we have structured our EU privacy and data protection compliance program in a UK-centric way. If UK and EU privacy and data protection laws and regulations diverge, we will be required to implement alternative EU compliance measures and adapt separately to any new UK requirements.
Additionally, our compliance with our privacy policy and our general consumer privacy practices are also subject to review by the Federal Trade Commission, which may bring enforcement actions to challenge allegedly unfair and deceptive trade practices, including the violation of privacy policies and representations therein. Certain State Attorneys General may also bring enforcement actions based on comparable state laws or federal laws that permit state-level enforcement. Outside of the United States, our privacy and data practices are subject to regulation by data protection authorities and other regulators in the countries in which we do business.
Beyond laws and regulations, we are also members of self-regulatory bodies that impose additional requirements related to the collection, use, and disclosure of consumer data, including the Internet Advertising Bureau ("IAB"), the Digital Advertising Alliance, the Network Advertising Initiative, and the Europe Interactive Digital Advertising Alliance. Under the requirements of these self-regulatory bodies, in addition to other compliance obligations, we provide consumers with notice via our privacy policy about our use of cookies and other technologies to collect consumer data, and of our collection and use of consumer data to deliver interest-based advertisements. We also allow consumers to opt-out from the use of data we collect for purposes of interest-based advertising through a mechanism on our website, linked through our privacy policy as well as through portals maintained by some of these self-regulatory bodies. Some of these self-regulatory bodies have the ability to discipline members or participants, which could result in fines, penalties, and/or public censure (which could in turn cause reputational harm). Additionally, some of these self-regulatory bodies might refer violations of their requirements to the Federal Trade Commission or other regulatory bodies.
Business Seasonality
Our advertising spend, revenue, cash flow from operations, Adjusted EBITDA, operating results, and other key operating and financial measures may vary from quarter to quarter due to the seasonal nature of buyer spending. For example, many buyers devote a disproportionate amount of their advertising budgets to the fourth quarter of the calendar year to coincide with increased holiday purchasing. We expect our revenue, cash flow, operating results and other key operating and financial measures to fluctuate based on seasonal factors from period to period and expect these measures to be higher in the fourth quarters than in prior quarters.
Working Capital Requirements
Our revenue is generated from advertising spend transacted on our platform using our technology solution. Generally, we invoice and collect from buyers the full purchase price for impressions they have purchased, retain our fees, and remit the balance to sellers. We attempt to coordinate collections from our buyers so as to fund our payment obligations to our sellers. However, in some cases, we may be required to pay sellers for impressions delivered before we have collected, or even if we are unable to collect, from the buyer of those impressions. There can be no assurances that we will not experience bad debt in the future. Any such write-offs for bad debt could have a materially negative effect on our results of operations for the periods in which the write-offs occur. In addition, growth and increased competitive pressure in the digital advertising industry are causing brand spenders to become more demanding, resulting in overall increased focus by all industry participants on pricing, transparency, and cash and collection cycles. Some buyers have experienced financial pressures that have motivated them to challenge some details of our invoices or to slow the timing of their payments to us. If buyers slow their payments to us or our cash collections are significantly diminished as a result of these dynamics, our revenue and/or cash flow could be adversely affected and we may need to use working capital to fund our accounts payable pending collection from buyers. This may result in additional cash expenditures and cause us to forego or defer other more productive uses of that working capital.

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Available Information
The Company is subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and accordingly files Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, proxy statements, and related amendments and other information with the Securities and Exchange Commission, or the SEC, pursuant to Sections 13(a) and 15(d) of the Exchange Act. Information filed by the Company with the SEC is available free of charge on the Company’s website at investor.rubiconproject.com as soon as reasonably practicable after such materials are filed with or furnished to the SEC. The public may read and copy any materials filed by the Company with the SEC at the SEC’s Public Reference Room at 100 F Street, NE, Washington, DC 20549 on official business days during the hours of 10:00 am to 3:00 pm. The public may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC at www.sec.gov. The contents of these websites are not incorporated into this Annual Report on Form 10-K or into any other report or document we file with the SEC, and any references to the URLs for these websites are intended to be inactive textual references only.

Item 1A. Risk Factors
Investing in our common stock involves a high degree of risk, including the risks described below, each of which may be relevant to decisions regarding an investment in or ownership of our stock. The occurrence of any of these risks could have a significant adverse effect on our reputation, business, financial condition, revenue, results of operations, growth, or ability to accomplish our strategic objectives, and could cause the trading price of our common stock to decline. You should carefully consider the risks set forth below and the other information contained in this report, including our consolidated financial statements and related notes and Management's Discussion and Analysis of Financial Condition and Results of Operations, before making investment decisions related to our common stock. However, this report cannot anticipate and fully address all possible risks of investing in our common stock, the risks of investing in our common stock may change over time, and additional risks and uncertainties that we are not aware of, or that we do not consider to be material, may emerge. Accordingly, you are advised to consider additional sources of information and exercise your own judgment in addition to the information we provide.
Risks Relating to Our Business, Growth Prospects and Operating Results
We made a strategic decision to reduce our pricing by lowering and then eliminating our buyer fees in 2017, resulting in significant revenue declines. We are now pursuing a higher volume, lower cost business model, which involves risks and may not succeed.
The ad tech market is demanding more efficiency and lower cost from intermediaries like us. In an effort to be more competitive in attracting demand and capturing inventory supply, we made a strategic decision in mid-2017 to reduce the fees we charged buyers in open market RTB transactions. In addition, in 2017 our business mix shifted to a higher proportion of header bidding transactions, and we charged lower buyer fees for header bidding transactions in order to pass higher bids to the downstream decisioning process. Finally, in response to increasing market pressure and in an effort to be more competitive, on November 1, 2017 we eliminated our buyer transaction fees altogether.
Buyer transaction fees represented approximately 51% of our revenue in 2016 and 49% of our revenue for the first ten months of 2017, which is the period during which we charged buyer fees in 2017. Consequently, the elimination of our buyer transaction fees has had a severe adverse effect on our revenue and margins. We must increase transactional activity on our platform dramatically to make up for this lost revenue and return to growth. A critical part of our plan to adjust to our lower take rates is to increase advertising spending on our platform and operate with improved efficiency that will support lower margins. To increase our advertising spend, we are taking steps to increase significantly the ad requests coming from our seller clients, which represent inventory available for purchase on our platform, and to increase the percentage of ad requests that we convert into successful transactions (fill rate). Our plans for increasing our inventory volumes include active pursuit of more direct relationships with sellers, particularly of mobile, video, and PMP impressions, which are areas of industry growth. We also plan to access ad requests that might not otherwise be accessible to us by utilizing emerging server-side header bidding technologies, including third-party wrappers, and also integrating with large sources of supply that have their own monetization capabilities but also allow third parties to connect to their exchanges and bid on their inventory. Our plans to improve our fill rate include using the technology we acquired from nToggle to filter out low-quality impressions so that a higher proportion of the ad requests on our platform are of interest to our buyers, and to enable our buyers to identify and purchase the impressions they want more efficiently. In addition, we expect the nToggle filtering technology to help us and our buyers control the processing costs associated with higher volumes of ad requests. These efforts require us to expend a significant amount of time and resources and may ultimately prove to be ineffective.   

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We may not succeed in increasing the inventory on our platform to the levels we expect for various reasons. Competitors could match our price reductions and develop their own filtering capabilities, thereby reducing competitive advantage we seek to develop. Sellers could decide to reduce the number of exchanges with which they integrate and choose competitors over us. Large sources of supply that have their own monetization capabilities and also allow us to connect to their exchanges and bid on their inventory could reduce the amount of inventory they sell through third parties, including us. Providers of third-party header bidding solutions could impose prohibitive terms. Even if we increase inventory on our platform as expected, much of that inventory growth will be through header bidding or other downstream decisioning arrangements; we must compete effectively with other sources of demand to purchase that inventory, which may be difficult if competitors have more robust demand or more effective technology or offer better pricing or service. In addition, operating at higher volumes with lower margins requires scale and efficiency, and we could have difficulty competing successfully with our largest competitors if the market evolves to aggressive price-cutting. Unless and until we are able to compensate for our price reductions by increasing advertising spend on our platform, our revenue will continue to decline, we will not be able to grow our business, our cash resources may be depleted, and we may be forced to seek additional capital to support our business and operations.  
While we work to increase the volume of transactions on our exchange, we must operate more cost-effectively to relieve the pressure on our margins and cash resources that has resulted from our price reductions. We must achieve overall cost controls despite the additional investments in technology and data processing capabilities required to support the increased volume of transactions on our exchange that our growth plans require. Therefore, in addition to the pursuit of our growth strategies, we are pursuing various cost-control measures. We are undertaking various efficiency initiatives including increased automation, bid filtering, office consolidation, reduction in general and administrative expenses, and other measures, all of which involve operational tradeoffs and involve risk, including increased risk of administrative error due to reduced staffing levels. If we are not able to improve the efficiency of our operations and succeed with our growth strategies, our business may not be viable.
We must grow rapidly to remain a market leader and to accomplish our strategic objectives. In order to meet our growth objectives, we will need to rely upon our ability to innovate, the continued adoption of our solution by buyers and sellers for higher value advertising inventory, the extension of the reach of our solution into evolving digital media, continued growth into new geographic markets, shift of our business mix to emphasize higher growth channels and ad units, and the implementation of new offerings. If we fail to grow, the value of our company may decline.
We must reverse the business declines we experienced in 2017 and grow significantly to keep pace with the growth and change in our market and to compete effectively. Growth depends upon the quality of our strategic vision and planning and our ability to compete effectively and meet the evolving needs of our clients. The advertising market is evolving rapidly, and if we make strategic errors, there is a significant risk that we will be unable to recover and achieve our objectives.
Historically, real-time bidding, or RTB, open-market transactions, particularly for desktop display advertising, have provided most of the activity on our platform. We expect our historical open-market RTB desktop display advertising business to continue to be an important source of revenue for us, but consistent with market trends, our RTB desktop display business has declined significantly as other transaction types and channels have absorbed a greater share of advertising spend. In addition, our share of the RTB desktop display market has diminished, largely because header bidding has allowed other exchanges to compete more effectively for inventory. Accordingly, our RTB desktop display business cannot be relied upon to drive growth. In order for us to grow and compete effectively, we must continue to increase our business in other transaction types, such as PMP transactions, other channels, such as mobile and out-of-home, and other advertising units, such as video, all of which are growth areas in the market, innovate to adapt to changing market conditions, further increase our international business in existing and new markets, and significantly expand the use of our PMP offerings. Mobile, video, and other emerging digital platforms require different technology and business expertise than display advertising, and also present other challenges that may be difficult for us to overcome, including inventory quality issues. Many of our competitors in these emerging platforms have a significant head start in terms of technology, buyer or seller relationships, and the scope of their product offerings. Furthermore, a growing percentage of online and mobile advertising spending is captured by owned and operated sites (such as Facebook and Google). Our business model may not translate well into higher-value advertising due to market resistance or other factors, and we may not be able to innovate quickly or successfully enough to compete effectively on new platforms, or to adapt our solution and infrastructure to international markets. New offerings may not correctly anticipate market demand, may not address demand as effectively as competing offerings, and may not deliver the results we expect.
Our technology development efforts may be inefficient or ineffective, which may impair our ability to attract buyers and sellers.
We face intense competition in the marketplace and are confronted by rapidly changing technology, evolving industry standards and consumer needs, and the frequent introduction of new solutions by our competitors that we must adapt and respond to. Our future success will depend in part upon our ability to enhance our existing solution and to develop and introduce competing new solutions in a timely manner with features and pricing that meet changing client and market requirements. Our solutions are complex and can require a significant investment of time and resources to develop, test, introduce into use, and enhance. These

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activities can take longer than we expect. We schedule and prioritize our development efforts according to a variety of factors, including our perceptions of market trends, client requirements, and resource availability; we may encounter unanticipated difficulties that require us to re-direct or scale back our efforts and we may need to modify our plans in response to changes in buyer and seller requirements, market demands, resource availability, regulatory requirements or other factors. If development of our solution becomes significantly more expensive due to changes in regulatory requirements or industry practices, or other factors, we may find ourselves at a disadvantage to larger competitors with more resources to devote to development. These factors place significant demands upon our engineering organization, require complex planning and decision making, and can result in acceleration of some initiatives and delay of others. If we do not manage our development efforts efficiently and effectively, we may fail to produce, or timely produce, solutions that respond appropriately to the needs of buyers and sellers, and competitors may develop offerings that more successfully anticipate market evolution and address market expectations. If our solution is not responsive and competitive, buyers and sellers can be expected to shift their business to competing solutions. Buyers and sellers may also resist adopting our new solutions for various reasons, including reluctance to disrupt existing relationships and business practices or to invest in necessary technological integration or preference for competitors' offerings or self-developed capabilities.
The emergence of header bidding may reduce the value of inventory available to us from sellers, and our header bidding solution may not result in revenue growth and may cause infrastructure strain and added cost.
Sellers have embraced header bidding, a technology solution by which impressions that would have previously been exposed to different potential sources of demand in a sequence dictated by ad server placement are instead available for concurrent competitive bidding by demand sources that use header bidding tags that the seller accepts. This can help sellers increase revenue by exposing their inventory to more bidders, thereby allocating more inventory to demand sources that value it most highly. However, the number of header bidding tags that sellers accept is limited because too many header bidding tags can cause delays in the transaction execution process, and therefore we must compete with other demand sources for sellers' header bidding slots. With sellers that accept our header bidding tags, we may be able to participate in improved demand dynamics by competing for impressions that would previously have been allocated first to demand sources prioritized above us in the seller's ad server, with accompanying potential for improved revenue. However, some sellers may not accept our header bidding tags, and our opportunities with those sellers may be impaired as a result. Certain sources of demand with unique value propositions may be prioritized by sellers in their allocation of available header bidding slots, leaving us to compete with other competitors for the remainder. Further, header bidding allows smaller competitors with less demand and/or fewer established seller relationships to compete for higher-value impressions on a more even footing. Just as header bidding allows us to compete with demand sources that would previously have been above us in sellers' ad server sequences, it exposes us to additional competition by demand sources that, prior to the emergence of header bidding, might have been below us in the sellers' ad server sequences or otherwise unable to compete effectively for inventory. This has contributed to our loss of market share for RTB desktop display inventory.
We have increased the number of installations of our header bidding solution with sellers. However, the productivity of our implementations to date has varied among sellers as a result of factors over which we have limited control, including seller systems and capabilities, technical proficiency of seller implementations, and other third-party code that sellers load onto their pages. As a result, many implementations require individualized adaptation and troubleshooting. Because header bidding has typically relied upon the consumer’s browser for execution, header bidding auctions can fail if the consumer’s browser is not updated or if the consumer’s internet connection is slow, and header bidding can cause increased load times for content, adversely affecting user experience. Mobile browsers present additional difficulties. One alternative is to migrate functionality away from the client-side to the server-side, which is more highly controlled and should support faster load times. We are pursuing server-side solutions, but they present their own challenges. Adding an additional step between the user’s browser and the demand source can cause increased latency and limit the amount of user data that is transmitted, contributing to difficulties in user data syncing and resulting adverse effects on audience targeting. Server-side technology also significantly increases the volume of demand sources that can be accommodated, resulting in increased competition for impressions. Further, the host of the server used in a particular transaction has an advantage in user synch with its demand sources, at least until some form of universal user identification approach gains significant market adoption. In the future, we plan to host more server-side header bidding solutions for our sellers, but this will increase our infrastructure costs, which we will not recover without increasing our fill rates.
As we invest in development of next-generation header bidding technology, we must continue working to improve the efficiency and effectiveness of our current header bidding solution and installations. Until we address these transitional issues, we will not fully offset the increased infrastructure costs associated with the higher volume of ad and bid requests we process as a result of header bidding; and we will not be able to take full advantage of the opportunities made available through current header bidding technology to access a larger addressable market and increase our revenue by capturing a greater share of higher value inventory. In addition, the expansion of header bidding exposes more inventory to competitive bidding, thereby potentially resulting in increased volatility of our operating results with little warning as a result of various factors, including evolution in technology and changes in business practices such as competitors’ bidding tactics and sellers’ ad server integration and management.

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We must increase the scale and efficiency of our technology infrastructure to support our growth and transaction volumes.
Our technology must scale to process the increased ad requests we anticipate on our platform. Additionally, for each individual advertising impression created when a user visits a website or uses an application where our auctions technology is integrated, our technology must send bid requests to appropriate and available buyers, receive and process their responses, select a winner, and, increasingly, integrate with third-party header bidding or other downstream decisioning systems. It must perform these transactions end-to-end within milliseconds. We must continue to increase the capacity of our platform to support our high-volume strategy, to cope with increased data volumes resulting from header bidding, increases in the number of buyers and sellers, and an increasing variety of advertising formats and platforms, and to maintain a stable service infrastructure and reliable service delivery. Delivering this increased capacity while concurrently reducing organizational costs to help compensate for our reduced revenue base will require us to implement more efficient data processing and traffic filtering. If we are unable, for cost or other reasons, to effectively increase the capacity of our platform, continue to process transactions at fast enough speeds, and support emerging advertising formats or services preferred by buyers, our revenue may be adversely affected by the inability to obtain new buyers or sellers, loss of existing buyers or sellers, or failure to process auction transactions in a timely manner. We expect to continue to invest in our platform to meet increasing demand. Such investment may negatively affect our profitability and results of operations, or cause dilution to our stockholders.
Our belief that there is significant and growing demand for our private marketplace solutions may be inaccurate, and we may not realize a return from our investments in that area.
We believe there is significant and growing demand for PMPs, and we have made significant investments to meet that demand through internal development efforts. The market for these solutions is still developing and may not grow as we expect, or it could have slow adoption rates for various reasons, including reluctance of some sellers to substitute our solution for transactions they have historically handled themselves through direct dealings with buyers. It is our expectation that PMPs may involve lower fees than we can charge for our real-time bidding services, which may not be fully offset by anticipated higher CPMs. In some cases, we have experienced fee pressure as we have built out our PMP offering, and we expect this fee pressure to increase as more competitors, including new entrants as well as sellers themselves, build their own technology and infrastructure to enter this business. Even if the market for these solutions develops as we anticipate, buyers and sellers might not embrace our offerings to the degree we expect due to various factors. For example, we may not be successful in building out these offerings consistent with our vision, or competitive offerings may be offered at lower prices or be perceived as having better features and functionality. We may also be unable to scale our solution to markets outside of the United States due to local currency or other specific regulatory or operational requirements that we are unable to comply with. Even if the market for these solutions develops as we anticipate, and our buyers and sellers embrace our offerings, the positive effect of our PMP offerings on our results of operations may be offset or negated if PMPs cannibalize our open marketplace transaction volumes or by similar offerings from our competitors or other adverse developments.
Our expectations regarding the growth prospects of our buyer offerings may be incorrect, and we may not realize a return from our investments in that area.
We compete for demand with well-established companies that have technological advantages stemming from their experience in the market. We must continue to adapt and improve our demand technology to compete effectively, and buyers may not embrace our offering due to various factors, including the perception that competitors have superior technology or produce better results. Buyers’ efforts to optimize their supply paths have resulted in demands for transparency, inventory quality accountability, and longer payment terms. Some buyers are demanding access to data that we are restricted from sharing by our arrangements with sellers. These factors may make it difficult for us to increase our business with some buyers, cause some buyers to reduce their spending with us, and increase our costs of doing business.
We have invested heavily in our mobile technology, which poses additional risks that did not affect our legacy desktop display business. Mobile connected devices, their operating systems, Internet browsers or content distribution channels, including those controlled by our competitors, may develop in ways that make it difficult for advertisements to be delivered to their users. Further, we rely upon relationships with third parties to provide our buyers with access to large numbers of mobile inventory sellers that utilize third-party technology to display ads. If our access to mobile inventory is limited by third-party technology or lack of direct relationships with mobile sellers, our ability to grow our business will be impaired.
Due to increased usage of mobile devices and resulting migration of advertising spending to mobile platforms, we have invested heavily in our mobile technology and are relying to a significant degree on our mobile offerings to fuel our continued growth. The mobile advertising market is growing and changing quickly, and technological, market, or regulatory developments could render our solution less competitive. Because mobile advertising uses different data-capture techniques and methods of recording payable transactions, caters to different buyer budgets, may require us to enter emerging markets in which we have less experience, including China and India, and involves development challenges imposed by differing technological requirements and

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standards, there can be no assurance that we will be successful in achieving our goals in this market. Moreover, buyers' spending to reach consumers through mobile advertising may evolve more slowly than expected, or not grow to levels we anticipate. Our mobile investment has been focused on real-time bidding of mobile impressions, and that market may not grow as we expect. Our mobile revenue growth depends to a significant degree on the success of our xAPI technology, which enables us to access inventory aggregated by third parties, and there can be no assurance that this technology will continue to work as anticipated, without costly bugs or errors. Our success in the mobile channel depends upon the ability of our technology solution to provide advertising for most mobile-connected devices, as well as the major operating systems or Internet browsers that run on them and the thousands of applications that are downloaded onto them. The design of mobile devices and operating systems, applications, or Internet browsers is controlled by third parties. These parties frequently introduce new devices and applications, and from time to time they may introduce new operating systems or Internet browsers or modify existing ones in ways that may significantly affect our business, such as by providing ad-blocking capabilities. Network carriers may also affect the ability to access specified content on mobile devices. If our solution is unable to work on these devices, operating systems, applications, or Internet browsers for any reason, our ability to generate revenue through mobile advertising could be significantly impaired.
Our growth depends upon our ability to attract and retain buyers and sellers and increase business with them. Buyers and sellers are free to direct their spending and inventory to competing sources of inventory and demand, and large competitors with direct mobile user relationships and proprietary first-party user data have invested early and heavily in mobile advertising solutions, have many established relationships with mobile buyers and sellers that may be difficult for us to replicate, and may provide more compelling solutions than we do. Most of the application providers selling inventory through our platform utilize software development kits, or SDKs, and other proprietary technology of third parties, such as aggregators, and it is those third parties, not the application providers themselves, that contract with us to provide exchange services to help monetize the inventory. Termination or diminution of our relationships with these third parties could result in rapid and significant reduction of the amount of mobile inventory available through our platform, which in turn would adversely affect our mobile advertising spend and growth prospects.
Fee issues could have a material adverse effect on our business.
A majority of our advertising spend comes from DSP buyers purchasing advertising inventory in RTB transactions on our platform. Prior to eliminating our buyer fees on November 1, 2017, our proprietary auction algorithms included a buyer fee for use of our technology, and we typically charged buyers a variable price for real-time bidding impressions without specifying the amount or method of determining the fee that was included in the price. Buyers and sellers sometimes questioned our buyer fees, and we experienced requests from buyers and sellers for discounts, fee concessions or revisions, rebates, refunds, and greater levels of pricing transparency and specificity, in some cases as a condition to maintain the relationship. This could continue with respect to historical buyer fees. In addition, we charge fees to sellers for use of our technology, typically as a percentage of the cost of media and we may decide to offer discounts or other pricing concessions in order to attract more inventory or demand, or to compete effectively with other providers that have different or lower pricing structures and may be able to undercut our pricing due to greater scale or other factors.
We also may face the risk that a buyer that is dissatisfied with the execution of a transaction on our platform could request a refund from us of the advertising spend on the transaction notwithstanding that we have only collected a fee on the transaction and may not have the ability to recover the full amount of spending associated with the transaction from the seller. Our revenue, take rate, the value of our business, and the price of our stock could be adversely affected if we cannot maintain and grow our revenue and profitability through volume increases that compensate for price reductions, or if we are forced to make significant fee concessions or refunds, or if buyers reduce spending with us or sellers reduce inventory available through our exchange due to fee disputes or pricing issues.
We have a history of losses and we need to sustain and increase investment in our technology in order to be competitive, but we face many risks that may prevent us from achieving or sustaining profitability in the future.
We reported a net losses of $154.8 million, $18.1 million, and $18.7 million during the years ended December 31, 2017, 2016, and 2014, respectively. During the year ended December 31, 2015, we reported net income of $0.4 million. As of December 31, 2017, we had an accumulated deficit of $253.8 million. During 2017, we were not able to sustain our earlier revenue growth and experienced significant declines in revenue and earnings for various reasons including our decisions to reduce and then eliminate our buyer fees. We have implemented strategic plans designed to reverse our financial declines and return to growth, and have taken steps to reduce unnecessary expenses and redirect spending to areas we expect to produce higher growth.
Notwithstanding these measures, revenue may continue to decrease due to competitive pressures, maturation of our business, or other factors, and additional cost-reduction measures may be required even as we must continue to increase investment in technology in response to industry developments and to retain competitiveness. We may not be able to return to revenue growth or to achieve or sustain profitability in the future.

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We have encountered and will continue to encounter risks and difficulties frequently experienced by growing companies in rapidly evolving industries, including allocating and making effective use of our limited resources; achieving market acceptance of our existing and future solutions; competing against companies with greater financial and technical resources; recruiting; integrating, motivating, and retaining qualified employees; developing relationships with buyers and sellers; developing new solutions; integrating new technologies or companies we acquire; and establishing and maintaining our corporate infrastructure, including internal controls relating to our financial and information technology systems. We must improve our current operational infrastructure and technology to support significant growth and to respond to the evolution of our market and competitors' developments. Our business prospects depend in large part on our ability to:
grow our share of online and mobile advertising spending and the supply of advertising impressions available to us notwithstanding the growing share of digital advertising that is controlled by owned and operated sites (such as Facebook and Google);
return to revenue growth and positive cash flow before depleting our cash resources to the point that our ability to fund our cash cycle and invest in our business is impaired;
build and maintain our reputation for innovation and solutions that meet the evolving needs of buyers and sellers;
distinguish ourselves from the wide variety of solutions available in our industry;
maintain and expand our relationships with buyers and sellers;
respond to evolving industry standards and government regulations that impact our business, particularly in the areas of data collection and consumer privacy;
prevent or otherwise mitigate failures or breaches of security or privacy;
attract, hire, integrate and retain qualified employees;
effectively execute upon our international expansion plans;
evaluate new acquisition targets, and successfully integrate acquired companies' businesses and technologies;
maintain our cloud-based technology solution continuously without interruption 24 hours a day, seven days a week; and
anticipate and respond to varying product life cycles and new advertising solutions such as header bidding, regularly enhance our existing advertising solutions, and introduce new advertising solutions and pricing models on a timely basis, including by developing our capabilities in evolving areas of the business, such as mobile and video.
As a result of various factors, our operating results may fluctuate significantly, be difficult to predict, and fall below analysts' and investors' expectations.
Our operating results may be difficult to predict, particularly because we generally do not have long-term contracts with buyers or sellers. We have experienced significant variations in revenue and operating results from period to period, and operating results may continue to fluctuate and be difficult to predict due to a number of factors, including:
seasonality in demand for digital advertising;
changes in pricing of advertising inventory or pricing for our solution and our competitors' offerings, including potential further reductions in our pricing and overall take rate as a result of competitive pressure, changes in supply, improvements in technology and extension of automation to higher-value inventory, uncertainty regarding rate of adoption, changes in the allocation of demand spend by buyers, changes in revenue mix, auction dynamics, pricing discussions or negotiations with clients and potential clients, header bidding and other factors;
diversification of our revenue mix to include new services, some of which may have lower pricing than our historic lower-value inventory business or may cannibalize existing business;
the addition or loss of buyers or sellers;
changes in the advertising strategies or budgets or financial condition of advertisers;
the performance of our technology and the cost, timeliness, and results of our technology innovation efforts;
advertising technology and digital media industry conditions and the overall demand for advertising, or changes and uncertainty in the regulatory environment for us or buyers or sellers, including with respect to privacy regulation;
the introduction of new technologies or service offerings by our competitors and market acceptance of such technologies or services;
our level of expenses, including investment required to support our technology development, scale our technology infrastructure and business expansion efforts, including acquisitions, hiring and capital expenditures, or expenses related to litigation;

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the impact of changes in our stock price on valuation of stock-based compensation or other instruments that are marked to market;
the effectiveness of our financial and information technology infrastructure and controls;
foreign exchange rate fluctuations; and
changes in accounting policies and principles and the significant judgments and estimates made by management in the application of these policies and principles.
Because significant portions of our expenses are relatively fixed, variation in our quarterly revenue could cause significant variations in operating results and resulting stock price volatility from period to period. In order to minimize adverse effects of our price reductions on revenue, we must increase the inventory and advertising spend on our platform and add more high-value inventory, which requires ongoing investment that can adversely affect earnings and might ultimately be unsuccessful. Period-to-period comparisons of our historical results of operations are not necessarily meaningful, and historical operating results may not be indicative of future performance. If our revenue or operating results fall below the expectations of investors or securities analysts, or below any guidance we may provide to the market, the price of our common stock could decline substantially.
Our revenue and operating results are highly dependent on the overall demand for advertising. Factors that affect the amount of advertising spending, such as economic downturns, can make it difficult to predict our revenue and could adversely affect our business.
Our business depends on the overall demand for advertising and on the economic health of our current and prospective sellers and buyers. If advertisers reduce their overall advertising spending, our revenue and results of operations are directly affected. Various macro factors could cause advertisers to reduce their advertising budgets, including adverse economic conditions and general uncertainty about economic recovery or growth, particularly in North America and Europe, where we do most of our business, instability in political or market conditions generally, and any changes in favorable tax treatment of advertising expenses and the deductibility thereof. Reductions in inventory due to loss of sellers would make our solution less robust and attractive to buyers.
Seasonal fluctuations in digital advertising activity could result in material fluctuations of our revenue, cash flows, operating results, and other key performance measures from period to period.
Our revenue, advertising spend, cash flow from operations, operating results, and other key performance measures may vary from quarter to quarter due to the seasonal nature of advertiser spending. For example, many advertisers devote a disproportionate amount of their advertising budgets to the fourth quarter of the calendar year to coincide with increased holiday purchasing, and advertising inventory in the fourth quarter may be more expensive due to increased demand for advertising inventory. As a result, any events that reduce the amount of advertising spend during the fourth quarter, or reduce the amount of inventory available to buyers during that period, could have a disproportionate adverse effect on our revenue and operating results for that fiscal year.
Failure to maintain our culture and institutional knowledge could jeopardize our innovation and operation effectiveness.
We have had significant attrition, including through workforce reductions, and it may become increasingly difficult to retain employees given concerns about our financial performance and significant reduction in the value of equity compensation resulting from the significant decline we have experienced in the market value of our common stock. Significant changes in our personnel may make it difficult for us to maintain our institutional knowledge and corporate culture, which has contributed significantly to our success in the past. If our culture and knowledge base are negatively affected, our ability to support our growth and innovation may diminish.
Risks Related to the Advertising Technology Industry, Market, and Competition
Market conditions are increasing the costs and risks of our operations.
Due to various factors, including header bidding, market pressure from the increasing share of the digital advertising economy absorbed by Google and Facebook, and demands by both buyers and sellers of digital advertising for increased efficiency and value throughout the ecosystem, business conditions are becoming more difficult for intermediary businesses like ours. We see this in various ways. Both demand and supply for digital advertising inventory outside the “walled garden” companies are becoming less unique, contributing to commodification of the business. Buyers and sellers are demanding more favorable trade terms, which puts pressure on our cash collections cycle and can require more of our cash to fund our payments, making it unavailable to invest in growth. Buyers increasingly require us to accept liability for inventory quality and sellers increasingly require us to accept liability for ad content, despite the fact that we are not in direct control of either. Increased buyer vigilance regarding non-human traffic and other inventory quality issues, and varying inconsistent methodologies for assessing inventory quality, are causing buyers increasingly to withhold payment for transactions they question. Buyers and sellers are increasingly insisting upon using their own

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data to resolve discrepancies in transaction counts more favorably to them, resulting in some revenue loss. These and similar trends increase the costs and risks of our operations and put pressure on our margins. 
The digital advertising market is relatively new, dependent on growth in various digital advertising channels, and vulnerable to adverse public perceptions and increased regulatory responses. If this market develops more slowly or differently than we expect, or if issues encountered by other participants or the industry generally are imputed to or affect us, our business, growth prospects and financial condition would be adversely affected.
While our core business of desktop display advertising has been used successfully for many years, marketing via new digital advertising channels, such as mobile and social media, out-of-home, and digital video advertising, are emerging and may evolve in unexpected ways, and our future growth will be constrained if we are not able to adapt successfully to market evolution. In addition, the success of our efforts to advance new solutions for increased advertising automation will depend upon adoption of our solution by personnel at buyers and sellers in lieu of their traditional methods of order placement. It is difficult to predict adoption rates, demand for our solution, the future growth rate and size of the digital advertising solutions market or the entry of competitive solutions.
Further, the digital advertising industry is complex and evolving, and the relatively few publicly traded companies operating in the business tend to be small and new to the public markets. Consequently, the digital advertising industry may not be as widely followed or understood in the financial markets as more mature industries. The markets may not fully appreciate our particular place in the industry and our strengths and differentiating factors. Problems experienced by one industry participant (even private companies) or issues affecting a part of the industry have the potential to have adverse effects on other participants in the industry or even the entire industry. Emerging understanding of how the digital advertising industry operates has spurred privacy concerns and misgivings about exploitation of consumer information and prompted regulatory responses that limit operational flexibility and impose compliance costs upon industry participants.
Any expansion of the market for digital advertising solutions depends on a number of factors, including social and regulatory acceptance, the growth of the overall digital advertising market and the growth of specific sectors including social, mobile, video, and out-of-home as well as the actual or perceived technological viability, quality, cost, performance and value associated with emerging digital advertising solutions. If demand for digital display advertising and adoption of automation does not continue to grow, or there is a reduction in demand for digital advertising caused by weakening economic conditions, decreases in corporate spending, quality, viewability, malware issues or other issues associated with buyers, advertising channels or inventory, negative perceptions of digital advertising, additional regulatory requirements, or other factors, or if we fail to develop or acquire capabilities to meet the evolving business and regulatory requirements and needs of buyers and sellers of multi-channel advertising, our competitive position will be weakened.
We operate in an intensely competitive market that includes companies that have greater financial, technical and marketing resources than we do.
We face intense competition in the marketplace. We compete for advertising spending against competitors that, in some cases, are also buyers and/or sellers on our platform. We also compete for supply of advertising inventory against a variety of competitors. Some of our existing and potential competitors are better established, benefit from greater name recognition, may have offerings and technology that we do not have or that are more evolved and established than ours, and have significantly more financial, technical, sales, and marketing resources than we do. In addition, some competitors, particularly those with greater scale or a more diversified revenue base and a broader offering, may have greater flexibility than we do to compete aggressively on the basis of price and other contract terms, or to compete with us by including in their product offerings services that we may not provide. Some competitors are able or willing to agree to contract terms that expose them to risks that might be more appropriately allocated to buyers or sellers of advertising (including inventory risk and the risk of having to pay sellers for unsold advertising impressions), and in order to compete effectively we might need to accommodate risks that could be difficult to manage or insure against. Some buyers that use our solution, and some potential buyers, have their own relationships with sellers or are seeking to establish such relationships and can directly connect advertisers with sellers, and many sellers are investing in capabilities that enable them to connect more effectively directly with buyers. Our business may suffer to the extent that buyers and sellers purchase and sell advertising inventory directly from one another or through other intermediaries other than us, reducing the amount of advertising spend on our platform. In addition, as a result of solutions introduced by us or our competitors, our marketplace will experience disruptions and changes in business models, which may result in our loss of buyers or sellers. Our innovation efforts may lead us to introduce new solutions that compete with our existing solutions. New or stronger competitors may emerge through acquisitions and industry consolidation or through development of disruptive technologies. If our offerings are not perceived as competitively differentiated, due to competition and growth in our industry or our failure to develop adequately to meet market evolution, we could lose clients and market share or be compelled to reduce our prices, making it more difficult to grow our business profitably.

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There has been rapid evolution and consolidation in the advertising technology industry, and we expect these trends to continue, thereby increasing the capabilities and competitive posture of larger companies, particularly those that are already dominant in various ways, and enabling new or stronger competitors to emerge. For example, while we are investing to participate in the shift of digital advertising spending to mobile channels, the mobile advertising market is dominated by a relatively small number of large competitors with direct mobile user relationships and proprietary first-party user data. These competitors have invested early and heavily in mobile advertising solutions that may be more compelling than ours, and have many established relationships with buyers and sellers that may be difficult for us to replicate. Similar dynamics can be expected as growth in digital video advertising brings established broadcast and content companies into the digital advertising business.
As technology continues to improve and market factors continue to attract investment by others in the business, competition and pricing pressure may increase and market saturation may change the competitive landscape in favor of larger competitors with greater scale and broader offerings, including those that can afford to spend more than we can to grow more quickly and strengthen their competitive position through innovation, development and acquisitions. In order to compete effectively, we may need to innovate, further differentiate our offerings, and expand the scope of our operations more quickly than would be feasible through our own internal efforts. However, because some capabilities may reside only in a small number of companies, our ability to accomplish necessary expansion through acquisitions may be limited because available companies may not wish to be acquired or may be acquired by larger competitors with the resources to outbid us, or we may need to pay substantial premiums to acquire those businesses. Our ability to make strategic acquisitions has also been hampered by the significant decline we have experienced in the value of our common stock, because our stock may not be viewed favorably as acquisition currency by an acquisition target, and the lower our stock price, the more dilution results from stock-based acquisitions.
Many buyers and sellers are large consolidated organizations that may need to acquire other companies in order to grow. Smaller buyers and sellers may need to consolidate in order to compete effectively. There is a finite number of large buyers and sellers in our target markets, and any consolidation of buyers or sellers may give the resulting enterprises greater bargaining power or result in the loss of buyers and sellers that use our platform, and thus reduce our potential base of buyers and sellers, each of which would lead to erosion of our revenue.
Acts of competitors and other third parties can adversely affect our business.
Our revenue is vulnerable to acts by third parties that reduce the amounts of spending or inventory available to us. For example, the amount of inventory available to independent platforms like us could be reduced as a result of decisions by Facebook to emphasize content viewable through its site or to favor friends-and-family type feeds over third-party properties, or decisions by Google to utilize its ad server advantages to outbid us and other competitors in open-market transactions. Similarly, decisions by buyers and sellers to transact directly rather than through us would tend to reduce both spending and inventory on our platform.
Our business depends on our ability to collect and use data to deliver advertisements, and to disclose data relating to the performance of advertisements. Any limitation imposed on our collection, use or disclosure of this data could significantly diminish the value of our solution and cause us to lose sellers, buyers, and revenue.
As we process transactions through our solution, we are able to collect significant amounts of information about advertisements, their buyers and sellers, and the transactions themselves. This includes buyer and seller preferences and requirements for media and advertisement content and specifications such as placement, size and format; pricing of advertisements; and auction activity such as price floors, bid response behavior, and clearing prices. We also are able to collect certain information about users, including browser or device location and characteristics; online behavior; exposure to and interaction with advertisements; and inferential data about purchase intentions and preferences. We collect this data through various means, including from our own systems, pixels, web beacons, software development kits installed in mobile applications, and cookies (which are discussed below). Our sellers and buyers also may provide us with their proprietary data about users.
We aggregate this data over trillions of advertising impressions and analyze it in order to enhance our services, including the pricing, placement and scheduling of advertisements purchased by buyers across the advertising inventory provided by sellers. We also share this data, or analyses based upon the data, with clients as part of our services. Our ability to collect, use, and share data about advertising purchase and sale transactions and user behavior and interaction with content is critical to the value of our services, and any limitation on our data practices could impair our ability to deliver effective solutions that meet the needs of sellers and buyers of advertising, resulting in loss of volume and reduced pricing.
Much of the data we collect and use belongs to our buyers or sellers, and we receive their permission to use it. (Other data is subject to control by Internet users, either as a result of regulation or through choices such as behavioral advertising opt-outs or use of ad blocking technologies, as discussed below). We use data related to our buyers and sellers and their transactional activity on our platform to facilitate our services, but we must exercise care not to use this data in ways that provide unfair advantages to, or adversely affect, buyers or sellers. Although our sellers and buyers generally permit us to aggregate and use data from advertising

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placements, subject to certain restrictions, sellers or buyers might decide to restrict our collection or use of their data. There could be various reasons for this, including perceptions by buyers that their data can be used by sellers to extract higher prices for impressions, or perceptions by sellers that their data can be used by buyers to bid tactically to reduce pricing for impressions. Buyers and sellers may also request that we discontinue using data obtained from their transactions that has already been aggregated with other data. It would be costly and difficult, if not impossible, to comply with such requests. As consumers continue to increase their use of digital technology and to incorporate multiple devices into their lives, linking and using data across such devices will become increasingly important. Various challenges affect our ability to link data relating to discrete devices or browsers, including different technologies, increased user awareness and sensitivity regarding use of data about their device usage, and evolving regulatory and self-regulatory standards. These challenges may slow growth, and if we are not able to cope with these challenges as effectively as other companies, we will be competitively disadvantaged. Any limitation on our ability to collect data about user behavior and interaction with content could make it more difficult for us to deliver effective solutions that meet the needs of sellers and buyers.
If the use of cookies is restricted or subject to unfavorable regulation, or cookies are replaced by alternative tracking mechanisms, our performance may decline and we may lose buyers and revenue.
We use "cookies," or small text files placed through an Internet browser on an Internet user's computer, to gather data to enable our solution to be more effective. Our cookies record certain user information, such as when an Internet user views or clicks on an advertisement, where a user is located, how many advertisements the user has seen, and browser or device information. We may also receive information from cookies placed by buyers or other parties who give us permission to use their cookies. We use data from cookies to help buyers decide whether to bid on, and how to price, an opportunity to place an advertisement in a certain location, at a given time, in front of a particular Internet user. Without cookie data, transactions occurring through our solution would be executed with less insight into activity that has taken place through an Internet user's browser, reducing the accuracy of buyers' decisions about which inventory to purchase for an advertising campaign. This could make placement of advertising through our solution less valuable, with commensurate reductions in pricing. If our ability to use cookies is limited, we may be required to develop or obtain additional applications and technologies to compensate for the lack of cookie data, which could be time consuming to develop or costly to obtain, less effective than our current use of cookies, and subject to additional regulation.
Cookies are an important component of our ability to provide a satisfactory offering to our clients, and our continued use of cookies is vulnerable to actions by sellers of inventory, consumers, and regulators. For example, the European Union, or EU, Privacy and Electronic Communications Directive (Directive 2002/58/EC), commonly referred to as the “Cookie Directive,” directs EU member states to ensure that Internet users consent to storing or accessing information on their devices, such as through a cookie. Because we lack a direct relationship with Internet users, we currently rely on our sellers to obtain such consent. Once the EU General Data Protection Regulation (“GDPR”) (as further described below) comes into effect, it may become more challenging for sellers to obtain effective consent under the Cookie Directive. In order to obtain effective consent, sellers must provide increasingly granular data to end users about cookies placed in the course of delivering an advertisement, including cookies placed by us, or by buyers using our technology. Providing this granular level of data may be difficult, and in some cases where a buyer is non-responsive or recalcitrant, may not be possible. Further, to the extent any seller does not adequately satisfy their consent obligations for our technology, we may face regulatory risk. As a result, these types of disclosure requirements, as well as any other limitations on our or our clients’ ability to place or use third-party cookies, may impair our ability to provide services in certain jurisdictions. The EU is also expected to replace the Cookie Directive with the ePrivacy Regulation. Current drafts of the ePrivacy Regulation propose significant requirements around obtaining consent, and impose fines for violations that are materially higher than those imposed under the Cookie Directive.
Separately, some prominent sellers have announced intentions to discontinue the use of cookies, and to develop alternative methods and mechanisms for tracking web users. It is possible that these companies may rely on proprietary algorithms or statistical methods to track web users without cookies, or may utilize log-in credentials entered by users into other web properties owned by these companies, such as their digital email services, to track web usage, including usage across multiple devices, without cookies. Alternatively, such companies may build different and potentially proprietary user tracking methods into their widely-used web browsers.
If cookies are effectively replaced by proprietary alternatives, our continued reliance upon cookie-based methods may face negative consumer sentiment and otherwise place us at a competitive disadvantage, compelling us to develop or license alternative proprietary tracking methodologies. Development would take time, potentially subjecting us to competitive disadvantages, and require substantial investment from us. Development also may not be commercially feasible given our relatively small size, the fact that development of such technologies may require technical skills that differ from our core engineering competencies, and the likelihood that the market would adopt solutions developed by larger competitors. Licensing new proprietary tracking mechanisms and data from companies that have developed them may not be viable for us for various reasons; creators of such technology may compete with us and may offer to provide the technology to us only on unfavorable terms or not at all, and if proprietary web

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tracking standards are owned by sellers or browser operators that have access to user information by virtue of their popular consumer-oriented websites or browsers and design their technology for use in conjunction with the types of user information collected from their websites or design their browser to disfavor third-party cookies, we may still be at a competitive disadvantage even if we license their technology.
If cookies are effectively replaced by open industry-wide tracking standards rather than proprietary standards, we may still incur substantial re-engineering costs to replace cookies with these new tracking technologies. This may also diminish the quality or value of our services to buyers if such new web-tracking technologies do not provide us with the quality or timeliness of the tracking data that we currently generate from cookies.
If the use of third-party cookies for digital advertising generally is rejected by Internet users, through opt-out or ad-blocking technologies or other means, or if other consumer choice mechanisms like “Do Not Track" and ”Limit Ad Tracking" inhibit our ability to collect and use data about end users, our performance may decline and we may lose buyers and revenue.
Internet users can, with increasing ease, implement practices or technologies that may limit our ability to collect and use data to deliver advertisements, or otherwise inhibit the effectiveness of our solution. First, cookies may easily be deleted or blocked by Internet users. All of the most commonly used Internet browsers allow Internet users to modify their browser settings to block first-party cookies (placed directly by the publisher or website owner that the user intends to interact with) or third-party cookies (placed by parties, like Rubicon Project, that have no direct relationship with the user), and some browsers, such as Safari, may block third-party cookies by default. Most browsers also now support temporary privacy modes that allow the user to suspend, with a single click, the placement of new cookies or reading or updates of existing cookies. Many applications and other devices allow users to avoid receiving advertisements by paying for subscriptions or other downloads. Mobile devices based upon the Android and iOS operating systems limit the ability of cookies to track users while they are using applications other than their web browser on their device. As a consequence, fewer of our cookies or sellers' cookies may be set in browsers or be accessible in mobile devices, which adversely affects our business.
Second, some Internet users also download free or paid "ad blocking" software, not only for privacy or security reasons, such as a desire to avoid being targeted for ads based upon location or online activity, but also to counteract the adverse effect advertisements can have on users' experience, including increased load times, data consumption, and screen overcrowding. Similar ad blocking technology has also recently emerged for mobile devices. Such ad blocking technology may prevent certain third-party cookies, or other tracking technologies, from being stored on a user's computer or mobile device. If more Internet users adopt these measures, our business could be harmed. Ad blocking technologies could have an adverse effect on our business if they reduce the volume or effectiveness (and therefore value) of advertising. In addition, some ad blocking technologies block only ads that are targeted through use of third-party data, while allowing ads based on first-party data (i.e. data owned by the provider of the website or application being viewed). These ad blockers could place us at a disadvantage because we rely on third-party data, while large competitors have troves of first-party data they use to direct advertising. Other technologies allow ads that are deemed "acceptable," which could be defined in ways that place us or our clients at a disadvantage, particularly if such technologies are controlled or influenced by our competitors. Even if ad blockers do not ultimately have a material impact on our business, investor concerns about ad blockers could cause our stock price to decline.
Increased prevalence of ad blocking has prompted examination of the effect of digital advertising industry practices upon the quality of user experiences, and changes in industry practices may emerge as a result. Such changes could reduce the viability of our existing business model, place us at a competitive disadvantage, or require us to invest significantly in developing new technologies and business practices.
Third, current versions of the most widely used web browsers allow users to send "Do Not Track" signals to indicate that they do not wish to have their web usage tracked. There is currently no definition of "tracking" and no set of commonly accepted standards regarding how to respond to a "Do Not Track" preference, but if such standards are implemented, either by applicable law or industry self-regulation, they could impose significant requirements and limitations on our data collection. Some proposed standards would allow first parties to continue to track users, even if the users have enabled the "Do Not Track" signal in their web browser, but would prevent third parties, like us, from any further tracking of such users across the Internet. Such a standard would place us at a significant competitive disadvantage compared to first-party data owners such as large website operators, many of whom own or are developing or acquiring capabilities that compete with our solution. Even absent an industry standard, various government authorities have indicated an intent to implement some type of "Do Not Track" standard. For example, the Federal Trade Commission, or FTC, and the European Commission, which proposes legislation to the European Parliament, have previously stated that they will pursue a legislative solution if the industry does not agree to a standard. Additionally, members of Congress have also issued public statements supporting the idea of a legislative solution. Such legislation or regulation may affect our ability to collect or use data collected through our platform when a user enables "Do Not Track," and may also include a distinction between first-party and third-party collection and usage of data, which may impact our ability to compete in the marketplace. We may separately elect to respond to any such legislation by adopting a policy to discontinue profiling or web tracking in response to

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"Do Not Track" requests, and it is possible that we could in the future be prohibited from using non-personal consumer data by industry standards or state or federal legislation, which may diminish our ability to target and improve advertisements and the value of our services.
Legislation and regulation of digital businesses, including privacy and data protection regimes, could create unexpected additional costs, subject us to enforcement actions for compliance failures, or cause us to change our technology solution or business model, which may have an adverse effect on the demand for our solution.
Many local, state, federal, and international laws and regulations apply to the collection, use, retention, protection, disclosure, transfer, and other processing of data collected from and about consumers and devices, and the regulatory framework for privacy issues is evolving worldwide. Various U.S. and foreign governments, consumer agencies, self-regulatory bodies, and public advocacy groups have called for new regulation directed at the digital advertising industry in particular, and we expect to see an increase in legislation and regulation related to the collection and use of data to target advertisements and communicate with consumers, including mobile device and cross-device data, geo-location data, anonymous Internet user data and unique device identifiers, such as IP address or mobile advertising identifiers, and the collection of data from apps and websites that are directed to children. Such legislation or regulation could affect the costs of doing business online and may adversely affect the demand for or the effectiveness and value of our solution. Some of our competitors may have more access to lobbyists or governmental officials and may use such access to effect statutory or regulatory changes in a manner that commercially harms us while favoring their solutions.
The U.S. government, including the FTC and the FCC, has announced that it is reviewing the need for greater regulation of the collection of consumer information, including regulation aimed at restricting some targeted advertising practices. For example, the U.S. Senate and certain state legislatures are considering enacting regulations that would place significant restrictions on the collection and use of geo-location data, including for advertising purposes. More recently, the FTC has issued guidance on how companies should apply privacy principles to tracking and delivery of targeted advertisements to consumers across multiple devices. The FTC has also adopted revisions to the Children's Online Privacy Protection Act that expand liability for the collection of information (including certain anonymous information such as persistent identifiers) by operators of websites and other online services that are directed to children or that otherwise use (for certain purposes) information collected from or about children. In addition, the European Union has adopted a General Data Protection Regulation, Regulation (EU) 2016/679 or the "GDPR," that will supersede the EU Data Protection Directive. The GDPR sets out higher potential liabilities for certain data protection violations, as well as a greater compliance burden for us in the course of delivering our solution in Europe. The regulatory climate in Europe, in particular, has grown increasingly unfavorable for advertising technology based business. Regulators have expressed antipathy towards common technologies deployed in digital advertising. As a result of the heightened consent and compliance obligations imposed by GDPR and anticipated under the ePrivacy Regulation, publishers may experience significantly higher rates of users who express a preference to limit the collection or use of certain data about them or their device, which could reduce the value of advertising to such users, with adverse effects on our revenue. European publishers may choose to monetize their content through non-advertising based methods, including but not limited to, converting to a subscription based website only.
The UK's decision to leave the European Union may add cost and complexity to our compliance efforts. The UK is an important geography for us and we have structured our EU privacy and data protection compliance in a UK-centric way by using our UK subsidiary as our EU data controller. If UK and EU privacy and data protection laws and regulations diverge, we will be required to implement alternative EU compliance mechanisms and adapt separately to any new UK requirements. Complying with any new regulatory requirements could force us to incur substantial costs, impact how clients view our technology, or require us to change our business practices in a manner that could reduce our revenue or compromise our ability to effectively pursue our growth strategy.
Further, many governments are restricting the transmission or storage of information about individuals beyond their national borders. Such restrictions could, depending upon their scope, limit our ability to utilize technology infrastructure consolidation, redundancy, and load-balancing techniques, resulting in increased infrastructure costs, decreased operational efficiencies and performance, and increased the risk of system failure.
These laws and regulations are continually evolving, not always clear, and not always consistent across the jurisdictions in which we do business. The measures we take to protect the security of information that we collect, use, and disclose in the operation of our business may not always be effective. Our failure to protect, and comply with applicable laws and regulations or industry standards applicable to, personal data or other data relating to consumers could result in enforcement action against us, including fines, imprisonment of our officers, and public censure, claims for damages by consumers and other affected individuals, damage to our reputation, and loss of goodwill. This is particularly true given that the FTC, Attorneys General of various U.S. States and various international regulators (including numerous data protection authorities in the European Union), have specifically cited as enforcement priorities certain practices that relate to digital advertising. Even the perception of concerns relating to our collection, use, disclosure, processing, and retention of data, including our security measures applicable to the data we collect, whether or not

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valid, may harm our reputation (and the reputation of the digital advertising ecosystem) and inhibit adoption of our solution by current and future buyers and sellers. We are aware of ongoing lawsuits filed against, or regulatory investigations into, companies in the digital advertising industry concerning various alleged violations of consumer protection, data protection, and computer crime laws, asserting various privacy-related theories. Any such proceedings brought against us could hurt our reputation, force us to spend significant amounts in defense of these proceedings, distract our management, increase our costs of doing business, adversely affect the demand for our services, and ultimately result in the imposition of monetary liability or restrictions on our ability to conduct our business. We may also be contractually liable to indemnify and hold harmless buyers or sellers from the costs or consequences of litigation or regulatory investigations resulting from using our services or from the disclosure of confidential information, which could damage our reputation among our current and potential sellers or buyers, require significant expenditures of capital and other resources and cause us to lose business and revenue.
Privacy and other regulatory violations by other participants in the digital advertising ecosystem could lead to increased regulatory and enforcement activities, reductions in the growth of demand for digital advertising, and increased user requirements, all of which could have adverse consequences and impose additional costs for all industry participants, including us.
The European Union's General Data Protection Regulation, which will take effect in May 2018 and restricts the transfer of personal data of EU residents to the United States, as well as pending legal cases in the European Union challenging certain transfers of such personal data outside of Europe, could require us to adopt costly compliance mechanisms, subject us to increased regulatory scrutiny, and hamper our plans to expand our business in Europe.
The use and transfer of personal data in EU member states is currently governed under Directive 95/46/EC (which is commonly referred to as the Data Protection Directive) as well as legislation adopted in the member states to implement the Data Protection Directive. The Data Protection Directive generally prohibits the transfer of personal data of EU subjects outside of the European Union, unless the party exporting the data from the European Union implements a compliance mechanism designed to ensure that the receiving party will adequately protect such data. We have relied on alternative compliance measures that directly subject us to regulatory enforcement by data protection authorities located in the European Union. As a result, we risk becoming the subject of regulatory investigations in any of the individual jurisdictions in which we operate. Each such investigation could cost us significant time and resources, and could potentially result in fines, criminal prosecution, or other penalties. Being forced to rely on alternative compliance measures could also affect the market for our technology, as EU clients may choose to do business with EU-based companies or other competitors that do not need to transfer personal data to the United States in order to avoid the above-identified risks and legal issues. Further, some of these alternative compliance measures are facing legal challenges, for example in Data Protection Commissioner v. Facebook and Maximillian Schrems, which was recently referred by the Irish High Court to the Court of Justice of the European Union. If these legal challenges successfully invalidate the alternative compliance measures that we currently rely on or may choose to rely on in the future, it may take us significant time, resources, and effort to restructure our business and/or rely on another legally sufficient compliance measure. Additionally, such an invalidation might affect our reputation with our clients, who may choose to work with businesses that do not rely on such compliance mechanisms, to ensure legal and regulatory compliance.
Additionally, the European Union has adopted the GDPR, which will supersede the Data Protection Directive in May 2018, or perhaps earlier in some jurisdictions. Among other requirements, the GDPR obligates companies that process large amounts of personal data about EU subjects to implement a number of formal processes and policies reviewing and documenting the privacy implications of the development, acquisition, or use of all new products, technologies, or types of data. Implementing these policies before the GDPR takes effect will take considerable time and resources, and could result in slowing our ability to develop, acquire, or enter into agreements to use new products, technologies, or types of data. By way of example, we must ensure that any recipient of personal data from data subjects in the EU can satisfy the adequate protection standards imposed by the EU. We may need to terminate relationships with third parties that do not satisfy these standards. In such case, we may have interruptions in our current client and vendor relationships, which may be disruptive and/or costly to our business. Further complicating this effort, the GDPR enables EU member states to enact jurisdiction-specific requirements in key areas, which could require us to modify our plans to comply with the GDPR, or otherwise to implement multiple policies unique to the jurisdictions in which we operate, which could make it more difficult and resource-intensive to continue to operate in the European Union. Additionally, the GDPR significantly increases the potential fines that might be awarded for violations of the regulation, in some cases permitting fines of up to 4% of a company’s total global turnover, though it remains unclear how EU data protection authorities will enforce the regulation and what penalties they may seek to impose on companies that violate the regulation. Finally, GDPR permits some forms of representative actions, which may be similar to class actions or collective actions in the United States. Allowing such representative actions may incentivize parties, organizations, and/or advocates to pursue private legal action relating to data protection violations more aggressively.
Current guidance on the obligations set forth in the GDPR remains sparse, so we have limited resources to draw upon as we develop our ongoing compliance practices. In particular, under the GDPR, a company is only permitted to process personal data if it

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satisfies one of the permitted grounds for processing data. For our core business operations, we are processing data in accordance with the “legitimate interest” grounds, which permit processing activities, provided the interests are not “overridden by the interests or fundamental rights and freedoms of the data subject.” There is minimal guidance on the factors that would override any legitimate interest for processing. To the extent our legal basis for processing data is called into question, we may be restricted from collecting and/or processing end user data within the EU. Moreover, if we are no longer able to rely on the “legitimate interest” grounds and must instead rely on “consent,” it may be difficult for our publishers to obtain effective consent on our behalf, and it may be difficult for us to obtain effective consent directly given our lack of direct relationships with end users and the lack of clear and consistent guidance by EU data protection authorities as to how third parties might obtain effective consent from end users. These complexities are compounded by the ability of different national and state governmental authorities within the EU to adopt differing interpretive and enforcement approaches to the law.
The GDPR significantly worsens the regulatory climate in the EU for ad tech generally. If European publishers react by choosing to monetize their content through non-advertising based methods (such as paid subscriptions), or reduce use of personal data subject to the GDPR in order to reduce compliance cost and risk, the volume and value of impressions available through our exchange would decrease, with potentially significant adverse consequences for our business.
The recently passed U.S. comprehensive tax reform bill could adversely affect our business and financial condition.
On December 22, 2017, the U.S. government enacted comprehensive Federal tax legislation commonly referred to as the Tax Cuts and Jobs Act of 2017 (“Tax Act”). The Tax Act, among other things, includes changes to U.S. federal tax rates, imposes future limitations on the deductibility of Research and Development (R&D) expenditures and net operating loss carryforwards, allows for the expensing of capital expenditures, and puts into effect the migration from a worldwide system of taxation to a territorial system. Our U.S. deferred tax assets and liabilities have been revalued as of December 31, 2017 at the newly enacted corporate rate and we have recorded a provisional estimate of our income at December 31, 2017 for the transition tax liability related to the deemed repatriation of all undistributed earnings from our foreign subsidiaries. The Tax Act could result in significant one time charges in future taxable years and increase our future U.S. tax expense. We are continuing to evaluate the Tax Act and its requirements, as well as its application to our business and its impact on our effective tax rate. At this stage, it is unclear how many U.S. states will incorporate these federal law changes, or portions thereof, into their tax codes. The implementation by us of new practices and processes designed to comply with and benefit from, the Tax Act and its rules and regulations could require us to make substantial changes to our business practices, allocate additional resources, and increase our costs, which could negatively affect our business, results of operations and financial condition.
We generally do not have contractual privity with Internet users who view advertisements that we place, and we may not be able to disclaim liabilities from such Internet users or consumers.
Potential sources of liability to Internet users include malicious activities, such as the introduction of malware into users' computers through advertisements served through our platform, and code that redirects users to sites other than the ones users sought to visit, potentially resulting in malware downloads or use charges from the redirect site. Sellers of advertisement space purchased through our solution often have terms of use in place with their users that disclaim or limit their potential liabilities to such users, or pursuant to which users waive rights to bring class-action lawsuits against the sellers related to advertisements. Certain of our competitors are also prominent sellers, and may be able to include protections in their website or application terms of use that also limit liability to users of their advertising services. We generally do not have terms of use in place with such users. As a consequence, we generally cannot disclaim or limit potential liabilities to such users through terms of use, which may expose us to greater liabilities than competing advertising networks that are also prominent sellers.
Changes in market standards applicable to our solution could require us to incur substantial additional development costs.
Market forces, competitors' initiatives, regulatory authorities, industry organizations, seller integration revisions, and security protocols are causing the emergence of demands and standards that are or could be applicable to our solution. We expect compliance with these kinds of standards to become increasingly important to buyers and sellers, and conforming to these standards is expected to consume a substantial and increasing portion of our development resources. If our solution is not consistent with emerging standards, our market position and sales could be impaired. If we make the wrong decisions about compliance with these standards, or are late in conforming, or if despite our efforts our solution fails to conform, our offerings will be at a disadvantage in the market to the offerings of competitors that have complied.
The evolving concept of viewability involves competitive uncertainty and may cause us to incur additional costs and liability risk.
Viewability of digital advertising inventory is relevant to marketers because it represents a way of assessing the value of particular inventory as a means to reach a target audience. However, there is no consensus definition of viewability. Some approaches focus on whether an advertisement can be seen at all, and others focus on whether an advertisement that can be seen is

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actually seen, in whole or part, or for how long. Low viewability can be caused by various factors, including technical issues (e.g. device screen size, browser functionality and settings, web site load times), media design (e.g. below-the-fold or sub-page placements), and user behavior (e.g. the decision whether to scroll down a website or click on an advertisement or how long to watch a video). Non-viewability is a separate issue and may result, for example, from stacking ads so the one in the back is obscured, or serving ads into a single pixel space too small to be seen.
Aside from non-viewable inventory, which is generally well understood, various vendors and other industry participants advocate definitions and measurements of low viewability that are consistent with their technology or interests. We cannot predict whether consensus views will emerge, or what they will be. Nevertheless, some themes seem to have emerged:
Buyers of advertising inventory are increasingly using technology, often provided by third parties, to assess viewability of impressions for use as a bidding or purchasing criterion, or to determine value for purposes of determining pricing.
Assessment of viewability is imperfect, but technology can be expected to improve as data providers, DSPs, and buyers themselves develop viewability assessment tools and build viewability factors into their algorithms for bidding, purchasing, and pricing decisions.
Inventory viewability and value correlate. More viewable inventory is more valuable, and viewability of inventory increases in importance with the price paid for that inventory.
Viewability can be used as an inventory differentiator, by domain or on an impression level, with higher viewability generally associated with higher value and pricing, and lower viewability generally associated with lower value and pricing.
These themes are relevant to our business of facilitating fully informed purchase and sale of advertising, and the evolution of viewability standards may represent an opportunity to refine matching of supply and demand. However, incorporating viewability concepts fully into our business as they evolve will require us to incur additional costs to integrate relevant technologies and process additional information through our system. If we do not handle viewability well, we could be competitively disadvantaged.
In addition, inventory that is well differentiated on the basis of viewability will also be differentiated on the basis of value, with less viewable inventory valued lower. In this context, if we are not positioned to transact the higher viewability inventory competitively, our revenue and profitability could be adversely affected.
Buyers could attempt to hold us responsible, and not to pay us, for impressions that do not satisfy their viewability requirements or expectations, and depending upon how viewability evolves, market practice or emerging regulation may require us to incur compliance costs and assume some responsibility for viewability of advertisements transacted through our solution. Divergent views of how to measure viewability and imperfect measurement technology could lead to disagreement, increasing risk of disputes, demands for refunds, and reputational harm.
Failure to comply with industry self-regulation could harm our brand, reputation and our business.
In addition to compliance with government regulations, we voluntarily participate in trade associations and industry self-regulatory groups that promulgate best practices or codes of conduct addressing privacy and the provision of digital advertising. However, in the past, some of these guidelines have not comported with our business practices, making them difficult for us to implement. If we encounter difficulties in the future, or our opt-out mechanisms fail to work as designed, or if digital media users misunderstand our technology or our commitments with respect to these principles, we may be subject to negative publicity, as well as investigation and litigation by governmental authorities, self-regulatory bodies or other accountability groups, buyers, sellers, or other private parties. Any such action against us could be costly and time consuming, require us to change our business practices, divert management's attention and our resources, and be damaging to our reputation and our business. In addition, we could be adversely affected by new or altered self-regulatory guidelines that are inconsistent with our practices or in conflict with applicable laws and regulations in the United States and other countries where we do business. As a result of such inconsistencies or conflicts, or other business or legal considerations, we may choose not to comply with some self-regulatory guidelines. Additionally, as we expand geographically, we may begin to operate in jurisdictions that have self-regulatory groups in which we do not participate. If we fail to abide by or are perceived as not operating in accordance with applicable laws and regulations and industry best practices, or any industry guidelines or codes with regard to privacy or the provision of Internet advertising, our reputation may suffer and we could lose relationships with buyers and sellers.

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Forecasts of market growth may prove to be inaccurate, and even if the market in which we compete achieves the forecasted growth, our business may not grow at similar rates, if at all.
We have in the past provided, and may continue to provide, forecasts related to our market, including forecasts relating to the expected growth in the digital advertising market and parts of that market as well as the forecasted trend towards automation of analog and print advertising markets. Growth forecasts are subject to significant uncertainty and are based on assumptions and estimates that may prove to be inaccurate. Moreover, the anticipation that the advertising industry will continue to shift from analog and print media to digital advertising at the rate forecasted, or the anticipation of the shift in advertising spending from analog to digital, may not come to fruition. Further, even if the market grows, we may not. Our plans to enter or increase our presence in various markets may not succeed for various reasons, including possible shortfall or misallocation of resources or superior technology development or marketing by competitors. Large competitors, principally Google and Facebook, have absorbed a large portion of recent growth in digital advertising spending and appear well positioned to continue to do so, making it more difficult for smaller companies like us to participate in market growth without taking share from competitors.
Risks Related to Our Relationships with Buyers and Sellers and Other Strategic Relationships
Our contracts with buyers and sellers are generally not exclusive and generally do not require minimum volumes or long-term commitments. If buyers or sellers representing a significant portion of the demand or inventory in our marketplace decide to materially reduce the use of our solution, we could experience an immediate and significant decline in our revenue and profitability and harm to our business.
Generally, our buyers and sellers are not obligated to provide us with any minimum volumes of business, may do business with our competitors as well as with us, may reduce or cancel their business with us without penalty, and may bypass us and transact directly with each other or through other intermediaries that compete with us. Accordingly, our business is highly vulnerable to changes in the macro environment, price competition, and development of new or more compelling offerings by our competitors, which could reduce business generally or motivate buyers or sellers to migrate to competitors' offerings.
Sellers and buyers may seek to change the terms on which they do business with us, or allocate their advertising inventory or demand to our competitors who provide advertising demand and supply to them on more favorable terms or whose offerings are considered more beneficial. Sellers may allocate their available inventory among channels according to various methodologies that often result in ranked prioritization in their ad servers. Competitors ranked higher in priority see available impressions earlier and have more opportunity to acquire more inventory and more high value inventory. It is easy for sellers to change rankings in their ad servers, and we cannot control how sellers rank us, and to the extent that competitors have higher priority than us, our revenue and the quality of inventory available to our buyers can be adversely affected. Supply of advertising inventory is also limited for some sellers, such as special sites or new technologies, and sellers may request higher prices, fixed price arrangements or guarantees that we cannot provide as effectively as our competitors, or that would reduce the profitability of that business. In addition, sellers sometimes place significant restrictions on the sale of their advertising inventory, such as strict security requirements, prohibitions on advertisements from specific advertisers or specific industries, and restrictions on the use of specified creative content or format. Finally, with the proliferation of header bidding, sellers' inventory could be available for purchase through multiple exchanges simultaneously, thereby potentially reducing the number of ad impressions sold through our exchange even where we have historically had relationships with the seller.
We serve many buyers and sellers, but certain large buyers and sellers have accounted for and will continue to account for a disproportionate share of business transacted through our solution. Buyer and seller needs and plans can change quickly, and buyers or sellers may reduce volumes or terminate their arrangements with us, quickly and without penalty, for a variety of reasons, including financial issues or other changes in circumstances; development or acquisition by buyers or sellers of their own technologies that reduce their reliance upon us; the new offerings by or strategic relationships with our competitors; change or removal of personnel with whom we traditionally had relationships; opportunities for buyers and sellers to bypass us and deal directly with each other; change in control (including consolidations through mergers and acquisitions); adoption of header bidding solutions; or declining general economic conditions (including those resulting from dissolutions of companies). Technical issues affecting our systems or the systems of our larger buyers or sellers could also cause a decline in spending. As is typical in our industry, some of the largest buyers and sellers on our platform are also competitors, which could increase the risk that such companies could reduce their business with us. These factors make it important for us to expand and diversify our client relationships. The number of large media buyers and sellers in the market is finite, and it could be difficult for us to replace revenue loss from any large buyers or sellers whose relationships with us diminish or terminate. Just as growth in our inventory strengthens buyer activity in a network effect, loss of inventory or buyers could have the opposite effect.
Because we do not have long-term contracts, our future revenue may be difficult to predict and there is no assurance that our current buyers and sellers will continue to use our solution or that we will be able to replace lost buyers or sellers with new ones. If a buyer or group of buyers representing a significant portion of the demand in our marketplace, or a seller or group of sellers

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representing a significant portion of the inventory in our marketplace decides to materially reduce use of our solutions, it could cause an immediate and significant decline in our revenue and profitability and harm to our business. Additionally, if we overestimate future usage, we may incur additional expenses in adding infrastructure without a commensurate increase in revenue, which would harm our profitability and other operating results.
We must provide value to both buyers and sellers of advertising without being perceived as favoring one over the other or being perceived as competing with them through our service offerings.
Buyers and sellers have different interests, with each trying to enhance its value in their transactions through use of data, requests that we adapt our solution to help them, and other means. We are interposed between buyers and sellers, and to be successful, we must continue to find ways of providing value to both without being perceived as favoring one at the expense of the other. For example, our proprietary auction algorithms, which are designed to improve auction outcomes, influence the allocation and pricing of impressions and must do so in ways that add value to both buyers and sellers. Continued technological evolution in our business results in the availability and use of more data more incisively to inform buying and selling decisions. Third-party data analytics providers encourage this dynamic by offering products to buyers and sellers to attempt to swing transactional dynamics to their advantage at the expense of the other. We come under pressure to provide raw data to fuel these products and to facilitate their use by buyers and sellers on our platform. Unlike some competitors, who focus on serving either buyers or sellers, we must serve the interests of both, meaning that we must exercise caution in use of data and may determine not to facilitate some data products, which could result in loss of business from clients that insist upon using such products. Furthermore, because new business models continue to emerge, we must constantly adapt our relationship with buyers and sellers and how we market ourselves to each. Consistent with our goal of connecting buyers and sellers, we inevitably grow closer to each, and we must take care that our deeper connections with buyers, on the one hand, or sellers, on the other hand, do not come at the expense of the other's interests. For example, our recent decision to default to a first-price auction dynamic for all our header bidding auctions could be perceived by some buyers as serving the interests of sellers by increasing amounts paid for inventory, while some sellers could view our Estimated Market Rate service, which is designed to reduce buyers’ first price bids while maintaining their win rates, as favoring buyers. In addition, as our own capabilities evolve, we may be perceived by clients, particularly buyers, as competing with them. If we fail to balance our clients' interests appropriately, our ability to provide a full suite of services and our growth prospects may be compromised.
We rely on buyers to use our solution to purchase advertising on behalf of advertisers. Such buyers may have or develop high-risk credit profiles or pay slowly, which may result in credit risk to us or require additional working capital to fund our accounts payable. In addition, direct billing arrangements between buyers and sellers may result in unfavorable fee dynamics and increased working capital demands.
Generally, we invoice and collect from buyers the full purchase price for impressions they have purchased, retain our fees, and remit the balance to sellers. However, in some cases, we may be required or choose to pay sellers for impressions delivered before we have collected, or even if we are unable to collect, from the buyer of those impressions. There can be no assurances that we will not experience bad debt in the future, and write-offs for bad debt could have a materially negative effect on our results of operations for the periods in which the write-offs occur. In addition, we attempt to coordinate collections from our buyers so as to fund our payment obligations to our sellers. However, some buyers and sellers may require direct billing and collection arrangements between themselves, and some providers of header bidding wrappers or other downstream decisioning mechanisms in which we participate (such as Google EBDA) may control billing and collection for transactions we win through their platforms. When we collect from buyers and pay sellers, we are able to retain our fees from cash we collect before remitting balances to sellers. However, if we do not manage collections and payments, we will need to invoice clients for our fees, which may delay our collections and increase visibility and result in pressure for more transparent or lower fees. Further, growth and increased competitive pressure in the digital advertising industry is causing brand spenders to become more demanding, resulting in overall increased focus by all industry participants on pricing, transparency, and cash and collection cycles. Some buyers have experienced financial pressures that have motivated them to slow the timing of their payments to us. If buyers slow their payments to us or our cash collections are significantly diminished as a result of these dynamics, our revenue and/or cash flow could be adversely affected and we may need to use working capital to fund our accounts payable pending collection from the buyers. This may result in additional costs and cause us to forgo or defer other more productive uses of that working capital.
Our sales efforts with buyers and sellers may require significant time and expense and may not yield the results we seek.
Attracting new buyers and sellers and increasing our business with existing buyers and sellers involves substantial time and expense, and we may not be successful in establishing new relationships or in maintaining or advancing our current relationships. We may spend substantial time and effort educating buyers and sellers about our offerings, including providing demonstrations and comparisons against other available solutions. This process can be costly and time-consuming, and is complicated by us having to spend time integrating our solution with software of buyers and sellers. Because our solution may be less familiar in some markets outside the United States, the time and expense involved with attracting, educating and integrating buyers and sellers in international

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markets may be even greater than in the United States. If we are not successful in targeting, supporting and streamlining our sales processes, our ability to grow our business may be adversely affected. In addition, because of competitive market conditions and negotiating leverage enjoyed by large buyers and sellers, we are sometimes forced to choose between loss of business or contracting on terms that allocate more risk to us than we would prefer to accept.
We rely on buyers and sellers to abide by contractual requirements and relevant laws, rules, and regulations when using our solution, and legal claims or enforcement actions resulting from the actions of buyers or sellers could expose us to liabilities, damage our reputation, and be costly to defend.
The buyers and sellers engaging in transactions through our platform impose various requirements upon each other, and they and the underlying advertisers are subject to regulatory requirements by governments and standards bodies applicable to their activities. We assume responsibility for satisfying or facilitating the satisfaction of some of these requirements through the contracts we enter into with buyers and sellers. In addition, we may have responsibility for some acts or omissions of buyers or sellers transacting business through our solution under applicable laws or regulations or as a result of common law duties, even if we have not assumed responsibility contractually. These responsibilities could expose us to significant liabilities, perhaps without the ability to impose effective mitigating controls upon, or to recover from, buyers and sellers.
We contractually require our buyers and sellers to abide by relevant laws, rules and regulations, as well as restrictions by their counterparties, when transacting on our platform, and we generally attempt to obtain representations from buyers that the advertising they place through our solution complies with applicable laws and regulations and does not violate third-party intellectual property rights, and from sellers about the quality and characteristics of the impressions they provide. We also generally receive representations from buyers and sellers about their privacy practices and compliance with applicable laws and regulations, including their maintenance of adequate privacy policies that disclose and permit our data collection practices. Nonetheless, there are many circumstances in which it is difficult or impossible for us to monitor or evaluate their compliance. For example, we cannot control the content of buyers’ advertisements or sellers’ media properties, and we are often unable to determine exactly what information a buyer collects after an ad has been placed, and how the buyer uses any such collected information. If buyers or sellers fail to abide by relevant laws, rules and regulations, or contract requirements, when transacting over our platform, or after such a transaction is completed, we could potentially face liability for such misuse. Similarly, if such misconduct results in enforcement action by a regulatory body or other governmental authority, we could become involved in a potentially time-consuming and costly investigation or we could be subject to some form of sanction or penalty. We may not have adequate indemnity to protect us against, and our policies of insurance may not cover, such claims and losses.
Our business relationships expose us to risk of substantial liability for contract breach, violation of laws and regulations, intellectual property infringement and other losses, and our contractual indemnities and limitations of liability may not protect us adequately.
Our agreements with sellers, buyers and other third parties typically obligate us to provide indemnity and defense for losses resulting from claims of intellectual property infringement, damages to property or persons, business losses or other liabilities. Generally, these indemnity and defense obligations relate to our own business operations, obligations and acts or omissions. However, under some circumstances, we agree to indemnify and defend contract counterparties against losses resulting from their own business operations, obligations and acts or omissions, or the business operations, obligations and acts or omissions of third parties. For example, because our business interposes us between buyers and sellers in various ways, buyers often require us to indemnify them against acts and omissions of sellers, and sellers often require us to indemnify them against acts and omissions of buyers. In addition, our agreements with sellers, buyers and other third parties typically include provisions limiting our liability to the counterparty and the counterparty's liability to us. These limits sometimes do not apply to certain liabilities, including indemnity obligations. These indemnity and limitation of liability provisions generally survive termination or expiration of the agreements in which they appear.
We have limited ability to control acts and omissions of buyers and sellers or other third parties that could trigger our indemnity obligations, and our policies of insurance may not cover us for acts and omissions of others. Because we contract with many buyers and sellers and those contracts are individually negotiated with different scopes of indemnity and different limits of liability, it is possible that in any case our obligation to provide indemnity for the acts or omissions of a third party such as a buyer or seller may exceed what we are able to recover from that party. Further, contractual limits on our liability may not apply to our indemnity obligations, contractual limits on our counterparties' liability may limit what we can recover from them, and contract counterparties may be unable to meet their obligations to indemnify and defend us as a result of insolvency or other factors. Large indemnity obligations, or obligations to third parties not adequately covered by the indemnity obligations of our contract counterparties, could expose us to significant costs.

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In addition to the effects on indemnity described above, the limitation of liability provisions in our contracts may, depending upon the circumstances, be too high to protect us from significant liability for our own acts or omissions, or so low as to prevent us from recovering fully for the acts or omissions of our counterparties.
Our solution relies on third-party open source software components. Failure to comply with the terms of the underlying open source software licenses could expose us to liabilities, and the combination of certain open source software with code that we develop could compromise the proprietary nature of our solution.
Our solution utilizes software licensed to us by third-party authors under "open source" licenses. The use of open source software may entail greater risks than the use of third-party commercial software, as open source licensors generally do not provide warranties or other contractual protections regarding infringement claims or the quality of the code. Some open source licenses contain requirements that we make available source code for modifications or derivative works we create based upon the type of open source software we use. If we combine our proprietary software with open source software in a certain manner, we could, under certain open source licenses, be required to release the source code of our proprietary software to the public. This would allow our competitors to create similar solutions with lower development effort and time and ultimately put us at a competitive disadvantage.
The terms of many open source licenses have not been interpreted by U.S. courts, and there is a risk that these licenses could be construed in a way that could impose unanticipated conditions or restrictions on us. Moreover, we cannot guarantee that our processes for controlling our use of open source software will be effective. If we are held to have breached the terms of an open source software license, we could be required to seek licenses from third parties to continue operating using our solution on terms that are not economically feasible, to re-engineer our solution or the supporting computational infrastructure to discontinue use of certain code, or to make generally available, in source code form, portions of our proprietary code.
Risks Relating to Our Operations
Our reorganization and cost-control efforts might not assure profitability and may affect morale and make it difficult to retain employees or attract new ones.
We implemented a reduction in force affecting approximately 125 employees in November 2016 and, in the first quarter of 2017, we exited the intent marketing business and reorganized our management team. These steps were part of a larger effort we began earlier in 2016 to realign our business to address the needs of our clients and the evolving marketplace in which we operate, and to pursue our strategic priorities. Our strategic decisions to reduce and then eliminate our buyer fees have contributed to a significant decline in our revenue and cash flow, which compelled us to pursue additional cost-reduction measures in the first quarter of 2018 in an ongoing effort to operate profitably. As a result, we implemented further headcount reductions of approximately 100 employees in the first quarter of 2018. We had previously scaled our organization in anticipation of continuing revenue growth in excess of the actual results we have achieved, and the steps we have taken are intended to reduce our costs to align our organization and cost structure more appropriately to our current revenue and scale and to position us better to expand our investments in future growth areas including header bidding, mobile, video, and PMP. However, our cost reduction efforts do not assure our profitability. Additional cost reductions may be implemented in the future, and cost savings may be offset by future hiring or other costs to pursue strategic objectives. The reduction in force and management reorganization could adversely affect morale in our organization and our reputation as an employer, which could lead to the loss of valued employees and could make it more difficult for us to hire new employees in the future, and the reduction of our headcount could adversely affect our service delivery and make it more difficult for us to pursue new opportunities and initiatives in the future.
Real or perceived errors or failures in the operation of our solution could damage our reputation and impair our sales.
We must operate our technology infrastructure without interruption to support the needs of sellers and buyers. Because our software is complex, undetected errors and failures may occur, especially when new versions or updates are made to our software or network infrastructure or changes are made to sellers' or buyers' software interfacing with our solution. Errors or bugs in our software, faulty algorithms, technical or infrastructure problems, or updates to our systems could lead to an inability to effect transactions or process data to place advertisements or price inventory effectively, cause the inadvertent disclosure of proprietary data, or cause advertisements to display improperly or be placed in proximity to inappropriate content. Despite testing by us, errors or bugs in our software have in the past, and may in the future, not be found until the software is in our live operating environment. For example, changes to our solution have in the past caused errors in the reporting and analytics applications for buyers, resulting in delays in their spending on our platform. Errors or failures in our solution, even if caused by the implementation of changes by buyers or sellers to their systems, could also result in negative publicity, disclosure of confidential information, damage to our reputation, loss of or delay in market acceptance of our solution, increased costs or loss of revenue, loss of competitive position, or claims by advertisers for losses sustained by them.

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We may make errors in the measurement of transactions conducted through our solution, causing discrepancies with the measurements of buyers and sellers, which can lead to a lack of confidence in us and require us to reduce our fees or provide refunds to buyers and sellers. Alleviating problems resulting from errors in our software could require significant expenditures of capital and other resources and could cause interruptions, delays, or the cessation of our business.
Various risks could interrupt access to our network infrastructure or data, exposing us to significant costs and other liabilities.
Our revenue depends on the technological ability of our solution to deliver and measure advertising impressions, and the operation of our exchange and our ability to place impressions depend on the continuing and uninterrupted performance of our IT systems. Our platform operates on our data processing equipment that is housed in third-party commercial data centers that we do not control. In addition, our systems interact with systems of buyers and sellers and their contractors. All of these facilities and systems are vulnerable to interruption and/or damage from a number of sources, many of which are beyond our control, including, without limitation: (i) loss of adequate power or cooling and telecommunications failures; (ii) fire, flood, earthquake, hurricane, and other natural disasters; (iii) software and hardware errors, failures, or crashes; (iv) financial insolvency; and (v) computer viruses, malware, hacking, terrorism, and similar disruptive problems. In particular, intentional cyber-attacks present a serious issue because they are difficult to prevent and remediate and can be used to defraud our buyers and sellers and their clients and to steal confidential or proprietary data from us, our clients, or their users. Further, because our Los Angeles headquarters and San Francisco offices and our California data center sites are in seismically active areas, earthquakes present a particularly serious risk of business disruption. These vulnerabilities may increase with the complexity and scope of our systems and their interactions with buyer and seller systems.
The steps we take to mitigate this risk may not protect against all problems, and our ability to mitigate risks to related third-party systems is limited. In addition, we rely to a significant degree upon security and business continuity measures of our data center operators, which may be ineffective. Our disaster recovery and business continuity plans rely upon third-party providers of related services, and if those vendors fail us, we could be unable to meet the needs of buyers and sellers. Any steps we take to increase the reliability and redundancy of our systems may be expensive and may not be successful in preventing system failures. Any failures with our solution or delays in the execution of transactions through our system may result in the loss of advertising placements on impressions and, as a result, the loss of revenue. Our facilities would be costly to repair or replace, and any such efforts would likely require substantial time.
Buyers may attribute to us any technical disruption or failure in the performance of advertisements on sellers' digital media properties, harming our reputation and resulting in buyers seeking to avoid payment or demand future credits for disruptions or failures. If we are unable to operate our exchange and deliver advertising impressions successfully, our ability to attract potential buyers and sellers and retain and expand business with existing buyers and sellers could be harmed.
Malfunction or failure of our systems, or other systems that interact with our systems, or inaccessibility or corruption of data, could disrupt our operations and negatively affect our business and results of operations to a level in excess of any applicable business interruption insurance, result in potential liability to buyers and sellers, and negatively affect our reputation and ability to sell our solution.
Any breach of our computer systems or confidential data in our possession could expose us to significant expense and liabilities and harm our reputation.
We maintain our own confidential and proprietary information in our IT systems, and we control or have access to confidential, proprietary, and personal data belonging or related to buyers, sellers, and their clients and users, as well as vendors and business partners. Our clients and various third parties also have access to our confidential and proprietary information. There is no guarantee that inadvertent or unauthorized use or disclosure will not occur or that third parties will not gain unauthorized access to this data despite our efforts to protect this data.
We are subject to ongoing security threats and breaches, computer malware, computer hacking attacks, and inadvertent transmission of computer viruses. Other harmful software code may occur on our systems or those of our clients, business partners, or information technology vendors. Security measures undertaken by us, our vendors, and our buyers and sellers may be ineffective as a result of employee error, failure to implement appropriate processes and procedures, malfeasance, cyber-attacks, cyber-extortion or other intentional misconduct by computer hackers, "phishing" or other tactics to obtain illicit system access, or otherwise. Because techniques used to obtain unauthorized access or sabotage systems change frequently and generally are not identified until they are launched against a target, and because we typically are not able to control the efficacy of security measures implemented by our clients and vendors, we may be unable to anticipate these techniques or to implement adequate preventative or mitigation measures.

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Though it is difficult to determine what harm may directly result from any specific interruption or breach, any security incident could disrupt computer systems or networks, interfere with services to our sellers, buyers, or their clients, and result in unauthorized access to personally identifiable information, intellectual property, and other confidential business information owned by us or our buyers, sellers, or vendors. As a result, we could be exposed to legal claims and litigation, indemnity obligations, regulatory fines and penalties, contractual obligations, other liabilities, significant costs for remediation and re-engineering to prevent future occurrences, significant distraction to our business, and damage to our reputation, our relationships with buyers and sellers, and our ability to retain and attract new buyers and sellers. If personally identifiable information is compromised, we may be required to undertake notification and remediation procedures, provide indemnity, and undergo regulatory investigations and penalties, all of which can be extremely costly and result in adverse publicity.
Failure to maintain the brand security features of our solution could harm our reputation and expose us to liabilities.
It is important to sellers that the advertising placed on their media not conflict with existing seller arrangements and be of high quality, consistent with applicable seller standards and compliant with applicable legal and regulatory requirements. It is important to buyers that their advertisements are placed on appropriate media, in proximity with appropriate content, that the impressions for which they are charged are legitimate, and that their advertising campaigns yield their desired results. We use various measures, including proprietary technology, in an effort to store, manage and process rules set by buyers and sellers and to ensure the quality and integrity of the results delivered to sellers and buyers through our solution. If we fail to properly implement or honor rules established by buyers and sellers, or if our measures are not adequate, advertisements may be improperly placed through our platform, which can result in harm to our reputation as well as the need to pay refunds and other potential legal liabilities.
Failure to detect or prevent fraud, intrusion of malware through our platform into the systems or devices of our clients and their customers, or other actions that impact the integrity of our solution or advertisement performance, could cause sellers and buyers to lose confidence in our solution and expose us to legal claims, which would cause our business to suffer. If we terminate relationships with sellers as a result of our screening efforts, our volume of paid impressions may decline.
We have in the past, and may in the future, be subject to fraudulent and malicious activities undertaken by persons seeking to use our platform for improper purposes, including to divert or artificially inflate purchases by buyers through our platform, or to disrupt or divert the operation of the systems and devices of our clients and their customers to misappropriate information, generate fraudulent billings, stage hostile attacks, or for other illicit purposes. Examples of such activities include the use of bots or other automated or manual mechanisms to generate fraudulent impressions that are delivered through our platform, which could overstate the performance of advertising impressions. Such activities could also include the introduction of malware through our platform by persons seeking to commandeer, or gain access to information on, consumers' devices. We use proprietary technology to identify non-human inventory and traffic, as well as malware, and we generally terminate relationships with parties that appear to be engaging in such activities, which may result in fewer paid impressions in the year the relationships are terminated than would have otherwise occurred. Despite our efforts, it can be difficult to detect fraudulent or malicious activity for various reasons. We do not own content and must rely in part on sellers and buyers for controls with respect to such activity. Perpetrators of fraudulent impressions and malware can be ingenious and change their tactics to adapt to preventative measures, requiring us to improve over time our processes for assessing the quality of sellers' inventory and controlling fraudulent activity. Fraudulent activity is more difficult for us to detect and police in inventory we access through third-party aggregators, because in those situations we do not connect directly to the publishers and their servers. We plan to increase our reliance on this type of inventory as part of our strategy to increase the volume of transactions on our platform, which could expose us to increased risk of fraudulent activity. If we fail to detect or prevent fraudulent or other malicious activity, we could face legal claims from clients and/or consumers and the affected advertisers may experience or perceive a reduced return on their investment or heightened risk associated with use of our solution, resulting in dissatisfaction with our solution, refusals to pay, refund demands, loss of confidence of buyers or sellers, or withdrawal of future business.
We are relying upon the ad classification technology we acquired from nToggle to help us increase the scale of our business and compete for demand.
In July 2017, we purchased nToggle, which had developed ad classification and filtering technology. Our plan is to use the technology to filter bidstream data to help our buyers more efficiently identify and purchase the inventory they are looking for, help our sellers monetize their inventory, and enable us to process ad requests more efficiently and achieve higher fill rates. As such, it is an important part of our strategic plans and is critical to our ability to increase the volume of transactional activity on our exchange significantly and in a cost-effective manner. We have invested substantially in continued development of the technology and the rollout of the classification and filtering capabilities to all of our buyers globally. The filtering stack is available in all of the US and Europe as of the first quarter of 2018, and Asia will be deployed by the second quarter of 2018. The current version of the technology is designed to eliminate low-value traffic for each buyer, and increase the amount of traffic that each buyer finds valuable, with the result that our traffic will be more valuable to our buyers than what they see from other exchanges. The

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technology requires additional development and its ongoing integration into our platform and implementation of the technology at scale in our services to our clients will continue to require significant efforts. We may need to allocate more resources to integration and product development activities than originally anticipated, and these efforts may increase the short-term cost of the deployment until we can more tightly integrate the features into our core platform. While we believe that the technology will give us a significant advantage in filtering capabilities over our competitors, some of our competitors are larger and better funded than we are, can devote more resources to development of technologies like filtering than we can, and thus might develop similar or better capabilities faster than we can. We intend to provide nToggle’s technology to our DSPs without charging separately for it, so we do not currently expect to generate revenue directly from sale of filtering services based upon nToggle’s technology. Instead, we plan to rely upon positive effects from integration of nToggle’s technology into our operations, as described above, to recover our investment in the acquisition and help us return to growth and positive cash flow. However, the results we expect from the nToggle technology might not materialize, and we may not be able to recoup our investment in the technology, potentially resulting in adverse effects on our strategic plans and negative effects on our results of operations, cash flows, and financial condition from acquisition-related charges, amortization of intangible assets and asset impairment charges. 
Any acquisitions we undertake may disrupt our business, adversely affect operations, dilute stockholders, and expose us to costs and liabilities.
Acquisitions have been an important element of our business strategy, and we may pursue future acquisitions in an effort to increase revenue, expand our market position, add to our service offering and technological capabilities, respond to dynamic market conditions, or for other strategic or financial purposes. However, there is no assurance that we will identify suitable acquisition candidates or complete any acquisitions on favorable terms, or at all. Further, any acquisitions we do complete would involve a number of risks, including the following:
The identification, acquisition, and integration of acquired businesses require substantial attention from management. The diversion of management's attention and any difficulties encountered in the transition process could hurt our business.
The identification, acquisition, and integration of acquired businesses requires significant investment, including to determine which new service offerings we might wish to acquire, harmonize service offerings, expand management capabilities and market presence, and improve or increase development efforts and technology features and functions.
The anticipated benefits from the acquisition may not be achieved, including as a result of loss of clients or personnel of the target, other difficulties in supporting and transitioning the target's clients, the inability to realize expected synergies from an acquisition, or negative culture effects arising from the integration of new personnel.
We may face difficulties in integrating the personnel, technologies, solutions, operations, and existing contracts of the acquired business.
We may fail to identify all of the problems, liabilities or other shortcomings or challenges of an acquired company, technology, or solution, including issues related to intellectual property, solution quality or architecture, income tax and other regulatory compliance practices, revenue recognition or other accounting practices, or employee or client issues.
To pay for future acquisitions, we could issue additional shares of our common stock or pay cash. Issuance of shares would dilute stockholders. Use of cash reserves could diminish our ability to respond to other opportunities or challenges. Borrowing to fund any cash purchase price would result in increased fixed obligations and could also include covenants or other restrictions that would impair our ability to manage our operations.
Acquisitions expose us to the risk of assumed known and unknown liabilities including contract, tax, and other obligations incurred by the acquired business or fines or penalties, for which indemnity obligations, escrow arrangements or insurance may not be available or may not be sufficient to provide coverage.
New business acquisitions can generate significant intangible assets that result in substantial related amortization charges and possible impairments.
The operations of acquired businesses, or our adaptation of those operations, may require that we apply revenue recognition or other accounting methodologies, assumptions, and estimates that are different from those we use in our current business, which could complicate our financial statements, expose us to additional accounting and audit costs, and increase the risk of accounting errors.
Acquired businesses may have insufficient internal controls that we must remediate, and the integration of acquired businesses may require us to modify or enhance our own internal controls, in each case resulting in increased

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administrative expense and risk that we fail to comply with the requirements of Section 404 of the Sarbanes-Oxley Act of 2002.
Acquisition of businesses based outside the United States would require us to operate in foreign languages and manage non-U.S. currency, billing, and contracting needs, comply with laws and regulations, including labor laws and privacy laws that in some cases may be more restrictive on our operations than laws applicable to our business in the United States.
Acquisitions can sometimes lead to disputes with the former owners of the acquired company, which can result in increased legal expenses, management distraction and the risk that we may suffer an adverse judgment if we are not the prevailing party in the dispute.
The purchase price allocation for any acquisition we complete is generally not finalized until well after the closing of the acquisition, and any final adjustment to the valuation could change the fair values assigned to the assets and liabilities, resulting in a change to our consolidated financial statements, including a change to goodwill. Such change could be material.
If we fail to attract, motivate, train, and retain highly qualified engineering, marketing, sales and management personnel, our ability to execute our business strategy could be impaired.
We are a technology-driven company and it is imperative that we have highly skilled mathematicians, computer scientists, engineers and engineering management to innovate and deliver our complex solutions. Increasing our base of buyers and sellers depends to a significant extent on our ability to expand our sales and marketing operations and activities, and our solution requires a sophisticated sales force with specific sales skills and specialized technical knowledge that takes time to develop. Appropriately qualified personnel can be difficult to recruit and retain. In addition, in international markets, we encounter staffing challenges that are unique to a particular country or region, such as recruiting and retaining qualified personnel in foreign countries and difficulty managing such personnel and integrating them into our culture. In particular, it may be difficult to find qualified sales personnel in international markets, or sales personnel with experience in emerging segments of the market. Skilled and experienced management is critical to our ability to achieve revenue growth, execute against our strategic vision and maintain our performance through the growth and change we anticipate.
Our success depends significantly upon our ability to recruit, train, motivate, and retain key technology, engineering, sales, and management personnel, and competition for employees with experience in our industry can be intense, particularly in California, New York and London, where our operations and the operations of other digital media companies are concentrated and where other technology companies compete for management and engineering talent. Other employers may be able to provide better compensation, more diverse opportunities and better chances for career advancement. These challenges could become more acute for us because our revenue and cash flow declines may contribute to concerns about our stability, and the decline we have experienced in the market value of our common stock reduces the perceived value of the equity compensation we offer and has left the stock options previously issued to our employees largely out of the money. Similarly, it may be difficult for us to recruit, train, motivate, and retain key technology, engineering, sales, and management personnel in light of the recent headcount reductions we have undertaken. None of our founders, officers, or other key employees has an employment agreement for a specific term, and any of such individuals may terminate his or her employment with us at any time.
It can be difficult, time-consuming, and expensive to recruit personnel with the combination of skills and attributes required to execute our business strategy, and we may be unable to hire or retain sufficient numbers of qualified individuals in the markets where we do business or plan to do business. New hires require significant training and it may take significant time (often six months or more) before they achieve full productivity. As a result, we may incur significant costs to attract and retain employees, including significant expenditures related to salaries and benefits and compensation expenses related to equity awards before new hires contribute to sales or productivity, and we may lose new employees to our competitors or other companies before we realize the benefit of our investment in recruiting and training. Moreover, new employees may not be or become as productive as we expect, and we may face challenges in adequately or appropriately integrating them into our workforce and culture. At times we have experienced elevated levels of unwanted attrition, and as our organization grows and changes and competition for talent increases, this type of attrition may increase.
Our proprietary rights may be difficult to enforce, which could enable others to copy or use aspects of our solution without compensating us, thereby eroding our competitive advantages and harming our business.
Our success depends, in part, on our ability to protect proprietary methods and technologies that we develop or otherwise acquire, so that we can prevent others from using our inventions and proprietary information. Establishing trade secret, copyright, trademark, domain name, and patent protection is difficult and expensive. We rely on trademark, copyright, trade secret laws, confidentiality procedures and contractual provisions to protect our proprietary methods and technologies. Our patent program is

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relatively small, and while we have some issued patents and pending patent applications, valid patents may not be issued from our pending applications or we may choose to abandon applications, and the claims of our issued patents or the claims eventually allowed on any pending applications may not be sufficiently broad to protect our technology or offerings and services. Any issued patents may be challenged, invalidated or circumvented, and any rights granted under these patents may not actually provide adequate defensive protection or competitive advantages to us. Additionally, the process of obtaining patent protection is expensive, time-consuming, and uncertain, and we may not be able to prosecute all necessary or desirable patent applications to successful conclusion at a reasonable cost or in a timely manner. Accordingly, despite our efforts, we may be unable to obtain adequate patent protection, or to prevent third parties from infringing upon or misappropriating our intellectual property.
Unauthorized parties may attempt to copy aspects of our technology or obtain and use information that we regard as proprietary, and the steps we take to protect our proprietary information may not prevent misappropriation of our technology and proprietary information or infringement of our intellectual property rights. Policing unauthorized use of our technology and intellectual property is difficult. We may be required to protect our intellectual property in an increasing number of jurisdictions, a process that is expensive and may not be successful or which we may not pursue in every location. Our competitors and others could attempt to capitalize on our brand recognition by using domain names or business names similar to ours, and we may be unable to prevent third parties from acquiring or using domain names and other trademarks that infringe on, are similar to, or otherwise decrease the value of our brands, trademarks or service marks. In addition, the laws of some foreign countries may not be as protective of intellectual property rights as those of the United States, and mechanisms for enforcement of our proprietary rights in such countries may be inadequate. Also, despite the steps we have taken to protect our proprietary rights, it may be possible for unauthorized third parties to copy or reverse engineer aspects of our technology or otherwise obtain and use information that we regard as proprietary, or to develop technologies similar or superior to our technology or design around our proprietary rights.
From time to time, we may take legal action to enforce our intellectual property rights, protect our trade secrets, determine the validity and scope of the proprietary rights of others, or defend against claims of infringement. Such litigation could result in substantial costs and the diversion of limited resources, and might not be successful. If we are unable to protect our proprietary rights (including aspects of our technology solution) we may find ourselves at a competitive disadvantage.
We may be subject to intellectual property rights claims by third parties, which are costly to defend, could require us to pay significant damages and could limit our ability to use certain technologies and intellectual property.
Third parties may assert claims of infringement or misappropriation of intellectual property rights against us or buyers, sellers, or third parties with which we work; we cannot be certain that we are not infringing any third-party intellectual property rights, and we may have liability or indemnification obligations as a result of such claims. As a result of the information disclosure in required public company filings our business and financial condition are visible, which may result in threatened or actual litigation, including by competitors and other third parties.
Regardless of whether claims that we are infringing patents or infringing or misappropriating other intellectual property rights have any merit, these claims are time-consuming and costly to evaluate and defend, and can impose a significant burden on management and employees. The outcome of any claim is inherently uncertain, and we may receive unfavorable interim or preliminary rulings in the course of litigation. There can be no assurances that favorable final outcomes will be obtained in all cases. We may decide to settle lawsuits and disputes on terms that are unfavorable to us. Some of our competitors have substantially greater resources than we do and are able to sustain the costs of complex intellectual property litigation to a greater degree and for longer periods of time than we could.
Although third parties may offer a license to their technology or intellectual property, the terms of any offered license may not be acceptable and the failure to obtain a license or the costs associated with any license could cause our business, results of operations or financial condition to be materially and adversely affected. In addition, some licenses may be non-exclusive, and therefore our competitors may have access to the same technology or intellectual property licensed to us. Alternatively, we may be required to develop non-infringing technology or to make other changes, such as to our branding, which could require significant effort and expense and ultimately may not be successful. Furthermore, a successful claimant could secure a judgment or we may agree to a settlement that prevents us from distributing certain products or performing certain services or that requires us to pay substantial damages, including treble damages if we are found to have willfully infringed such claimant's patents or copyrights. Claims of intellectual property infringement or misappropriation also could result in injunctive relief against us, or otherwise result in delays or stoppages in providing all or certain aspects of our solution.
We are subject to government regulations concerning our employees, including wage-hour laws and taxes.
We are subject to applicable rules and regulations relating to our relationship with our employees, including health benefits, sick days, unemployment and similar taxes, overtime and working conditions, equal pay, immigration status, and classification of employee benefits for tax purposes. Legislated increases in labor cost components, such as employee benefit costs, workers'

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compensation insurance rates, compliance costs and fines, as well as the cost of litigation in connection with these regulations, would increase our labor costs. Many employers nationally have been subject to actions brought by governmental agencies and private individuals under wage-hour laws on a variety of claims, such as improper classification of workers as exempt from overtime pay requirements, failure to pay overtime wages properly, and failure to provide meal and rest breaks or pay for missed breaks, with such actions sometimes brought as class actions, and these actions can result in material liabilities and expenses. Federal and state standards for classifying employees under wage-hour laws differ and are often unclear or require application of judgment, and classification may need to be changed as employment duties evolve over time. We may mis-classify employees and be subject to liability as a result. If we become subject to employment litigation, such as actions involving wage-hour, overtime, break and working time, it may distract our management from business matters and result in increased labor costs.
Risks Related to Our International Business Strategy
Our international operations require increased expenditures and impose additional risks and compliance imperatives, and failure to successfully execute our international plans will adversely affect our growth and operating results.
We have numerous operations outside of North America, in Northern and Southern Europe, Australia, Japan, Singapore, and Brazil, and achievement of our international objectives will require a significant amount of attention from our management, finance, legal, analytics, operations, sales, and engineering teams, as well as significant investment in developing the technology infrastructure necessary to deliver our solution and maintain sales, delivery, support, and administrative capabilities in the countries where we operate. Attracting new buyers and sellers outside the United States may require more time and expense than in the United States, in part due to language barriers and the need to educate such buyers and sellers about our solution, and we may not be successful in establishing and maintaining these relationships. The data center and telecommunications infrastructure in some overseas markets may not be as reliable as in North America and Europe, which could disrupt our operations. In addition, our international operations will require us to develop and administer our internal controls and legal and compliance practices in countries with different cultural norms, languages, currencies, legal requirements, and business practices than the United States.
International operations also impose risks and challenges in addition to those faced in the United States, including management of a distributed workforce; the need to adapt our offering to satisfy local requirements and standards (including differing privacy policies and labor laws that are sometimes more stringent); laws and business practices that may favor local competitors; legal requirements or business expectations that agreements be drafted and negotiated in the local language and disputes be resolved in local courts according to local laws; the need to enable transactions in local currencies; longer accounts receivable payment cycles and other collection difficulties; the effect of global and regional recessions and economic and political instability; potentially adverse tax consequences in the United States and abroad; staffing challenges, including difficulty in recruiting and retaining qualified personnel as well as managing such a diversity in personnel; reduced or ineffective protection of our intellectual property rights in some countries; and costs and restrictions affecting the repatriation of funds to the United States.
One or more of these requirements and risks may make our international operations more difficult and expensive or less successful than we expect, and may preclude us from operating in some markets. There is no assurance that our international expansion efforts will be successful, and we may not generate sufficient revenue or margins from our international business to cover our expenses or contribute to our growth.
Operating in multiple countries requires us to comply with different legal and regulatory requirements.
Our international operations subject us to laws and regulations of multiple jurisdictions, as well as U.S. laws governing international operations, which are often evolving and sometimes conflict. For example, the Foreign Corrupt Practices Act, or FCPA, and comparable foreign laws and regulations (including the U.K. Bribery Act) prohibit improper payments or offers of payments to foreign governments and their officials and political parties by U.S. and other business entities for the purpose of obtaining or retaining business. Other laws and regulations prohibit bribery of private parties and other forms of corruption. As we expand our international operations, there is some risk of unauthorized payment or offers of payment or other inappropriate conduct by one of our employees, consultants, agents, or other contractors, including by persons engaged or employed by a business we acquire, which could result in violation by us of various laws, including the FCPA. Safeguards we implement to discourage these practices may prove to be ineffective and violations of the FCPA and other laws may result in severe criminal or civil sanctions, or other liabilities or proceedings against us, including class action lawsuits and enforcement actions from the SEC, Department of Justice, and foreign regulators. Other laws applicable to our international business include local employment, tax, privacy, data security, and intellectual property protection laws and regulations, including restrictions on movement of information about individuals beyond national borders. In particular, as explained in more detail elsewhere in this report, the EU General Data Protection Regulation, which becomes effective in May 2018, will impose substantial compliance obligations and increase the risks associated with collection and processing of personal data. In some cases, buyers and sellers operating in non-U.S. markets may impose additional requirements on our non-U.S. business in efforts to comply with their interpretation of their own or our legal obligations. These requirements may differ significantly from the requirements applicable to our business in the United States and

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may require engineering, infrastructure and other costly resources to accommodate, and may result in decreased operational efficiencies and performance. As these laws continue to evolve and we expand to more jurisdictions or acquire new businesses, compliance will become more complex and expensive, and the risk of non-compliance will increase.
Compliance with complex foreign and U.S. laws and regulations that apply to our international operations increases our cost of doing business abroad, and violation of these laws or regulations may interfere with our ability to offer our solution competitively in one or more countries, expose us or our employees to fines and penalties, and result in the limitation or prohibition of our conduct of business.
We are subject to governmental export and import controls that could subject us to liability or impair our ability to compete in international markets.
Our operations are subject to U.S. export controls, specifically the Export Administration Regulations and economic sanctions enforced by the Office of Foreign Assets Control. These regulations limit and control export of encryption technology. Furthermore, U.S. export control laws and economic sanctions prohibit the shipment of certain products and services to countries, governments, and persons targeted by U.S. sanctions. We incorporate encryption technology into the servers that operate our solution. As a result of locating some servers in data centers outside of the United States, we must comply with these export control laws.
In addition, various countries regulate the import of certain encryption technology and have enacted laws that could limit our ability to deploy our technology or our clients' ability to use our solution in those countries. Changes in our technology or changes in export and import regulations may delay introduction of our solution or the deployment of our technology in international markets, prevent our clients with international operations from using our solution globally or, in some cases, prevent the export or import of our technology to certain countries, governments or persons altogether. Any change in export or import regulations, economic sanctions or related legislation, shift in the enforcement or scope of existing regulations, or change in the countries, governments, persons, or technologies targeted by such regulations, could result in decreased use of our solution by, or in our decreased ability to export our technology to, international markets.
Fluctuations in the exchange rates of foreign currencies could result in currency transaction losses.
We currently have transactions denominated in various non-U.S. currencies, and may, in the future, have sales denominated in the currencies of additional countries. In addition, we incur a portion of our expenses in non-U.S. currencies, and to the extent we need to convert currency to pay expenses, we are exposed to potentially unfavorable changes in exchange rates and added transaction costs. We expect international transactions to become an increasingly important part of our business, and such transactions may be subject to unexpected regulatory requirements and other barriers. Any fluctuation in relevant currency exchange rates may negatively impact our business, financial condition and results of operations. We have not previously engaged in foreign currency hedging, and any effort to hedge our foreign currency exposure may not be effective due to lack of experience, unreasonable costs or illiquid markets. In addition, hedging may not protect against all foreign currency fluctuations and can result in losses.
Risks Related to Our Internal Controls and Finances
Failure to maintain effective internal controls could cause our investors to lose confidence in us and adversely affect the market price of our common stock. If our internal controls are not effective, we may not be able to accurately report our financial results or prevent fraud.
Section 404 of the Sarbanes-Oxley Act of 2002 requires that we maintain internal control over financial reporting that meets applicable standards and report on the effectiveness of our internal controls over financial reporting and any material weaknesses we identify. When we are no longer an "emerging growth company," we will also need to provide a statement that our independent registered public accounting firm has issued an opinion on our internal control over financial reporting.
We may err in the design or operation of our controls, and all internal control systems, no matter how well designed and operated, can provide only reasonable assurance that the objectives of the control system are met. Because there are inherent limitations in all control systems, there can be no absolute assurance that all control issues have been or will be detected. We previously identified certain material weaknesses in our internal controls which were remediated during 2014. However, completion of remediation does not provide assurance that our remediated controls will continue to operate properly or that our financial statements will be free from error. There may be undetected material weaknesses in our internal control over financial reporting, as a result of which we may not detect financial statement errors on a timely basis. Moreover, in the future we may implement new offerings and engage in business transactions, such as acquisitions, reorganizations, or implementation of new information systems

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that could require us to develop and implement new controls and could negatively affect our internal control over financial reporting and result in material weaknesses.
If we identify new material weaknesses in our internal control over financial reporting, if we are unable to comply with the requirements of Section 404 in a timely manner, or, once required, if our independent registered public accounting firm is unable to express an opinion as to the effectiveness of our internal control over financial reporting, we may be unable, or be perceived as unable, to produce timely and reliable financial reports, investors may lose confidence in the accuracy and completeness of our financial reports, and the market price of our common stock could be negatively affected. As a result of such failures, we could also become subject to investigations by the stock exchange on which our securities are listed, the SEC, or other regulatory authorities, and become subject to litigation from investors and stockholders, which could harm our reputation, financial condition, or divert financial and management resources from our core business.
Our accounting is complex, and relies upon estimates or judgments relating to our critical accounting policies. If our accounting is erroneous or based on assumptions that change or prove to be incorrect, our operating results could fall below the expectations of securities analysts and investors, resulting in a decline in our stock price.
The preparation of financial statements in conformity with generally accepted accounting principles in the United States, or GAAP, requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes, and also to comply with many complex requirements and standards. Various factors contribute to complexity in our accounting. For example, the recognition of our revenue is governed by certain criteria that determine whether we report revenue either on a gross basis, as a principal, or net basis, as an agent, depending upon the nature of the sales transaction. We have generally reported our revenue on a net basis because we are not the principal in our open market and orders transactions as conducted to date. However, from April 2015 through January 2017, we conducted an intent marketing business that included transactions reported on a gross basis, resulting in higher GAAP revenue and lower GAAP margins on a particular amount of advertising spend than for an equivalent level of advertising spend for which we report revenue on a net basis. We may have gross reporting for portions of our revenue in the future as a result of the evolution of our existing business practices, development of new products, acquisitions, or changes in accounting standards or interpretations, that in any case result in transactions with characteristics that dictate gross reporting. It is also possible that revenue reporting for existing business may change from gross to net or vice versa as a result of changes in contract terms or transaction mechanics. We may experience significant fluctuations in revenue in future periods depending upon, in part, the nature of our sales and our reporting of such revenue and related accounting treatment, without proportionate correlation to our underlying activity or net income. Any combination of net and gross revenue reporting would require us to make estimates and assumptions about the mix of gross and net-reported transactions based upon the volumes and characteristics of the transactions we think will make up the total mix of revenue in the period covered by the projection. Those estimates and assumptions may be inaccurate when made, or may be rendered inaccurate by subsequent circumstances, such as changing the characteristics of our offerings or particular transactions in response to client demands, market developments, regulatory pressures, acquisitions, and other factors. Even apparently minor changes in transaction terms from those initially envisioned can result in different accounting conclusions from those foreseen. In addition, we may incorrectly extrapolate from revenue recognition treatment of prior transactions to future transactions that we believe are similar, but that ultimately are determined to have different characteristics that dictate different revenue reporting treatment. These factors may make our financial reporting more complex and difficult for investors to understand, may make comparison of our results of operations to prior periods or other companies more difficult, may make it more difficult for us to give accurate guidance, and could increase the potential for reporting errors.
Further, our acquisitions have imposed purchase accounting requirements, required us to integrate accounting personnel, systems, and processes, necessitated various consolidation and elimination adjustments, and imposed additional filing and audit requirements. Ongoing evolution of our business, and any future acquisitions, will compound these complexities. Our operating results may be adversely affected if we make accounting errors or our judgments prove to be wrong, assumptions change or actual circumstances differ from those in our assumptions, or acquired assets become impaired, which could cause our operating results to fall below the expectations of securities analysts and investors or guidance we may have provided, resulting in a decline in our stock price and potential legal claims. Significant judgments, assumptions and estimates used in preparing our consolidated financial statements include those related to revenue recognition, stock-based compensation, purchase accounting, assessment of goodwill and long-lived assets for impairment, and income taxes.
Our tax liabilities may be greater than anticipated.
The U.S. and non-U.S. tax laws applicable to our business activities are subject to interpretation. We are subject to audit by the Internal Revenue Service and by taxing authorities of the state, local, and foreign jurisdictions in which we operate. Our tax obligations are based in part on our corporate operating structure, including the manner in which we develop, value, and use our intellectual property and sell our solution, the jurisdictions in which we operate, how tax authorities assess revenue-based taxes such as sales and use taxes, the scope of our international operations, and the value we ascribe to our intercompany transactions. Taxing

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authorities may challenge our tax positions and methodologies for valuing developed technology or intercompany arrangements, as well as our positions regarding jurisdictions in which we are subject to certain taxes, which could expose us to additional taxes and increase our worldwide effective tax rate. Any adverse outcomes of such challenges to our tax positions could result in additional taxes for prior periods, interest, and penalties, as well as higher future taxes. In addition, our future tax expense could increase as a result of changes in tax laws, regulations, or accounting principles, or as a result of earning income in jurisdictions that have higher tax rates. An increase in our tax expense could have a negative effect on our financial position and results of operations. Moreover, determining our provision (benefit) for income taxes and other tax liabilities requires significant estimates and judgment by management, and the tax treatment of certain transactions is uncertain. Although we believe we will make reasonable estimates and judgments, the ultimate outcome of any particular issue may differ from the amounts previously recorded in our financial statements and any such occurrence could materially affect our financial position and results of operations.
Our ability to use our net operating losses and tax credit carryforwards to offset future taxable income may be subject to certain limitations, which could result in higher tax liabilities.
Our ability to fully utilize our net operating loss and tax credit carryforwards to offset future taxable income may be limited. At December 31, 2017, we had U.S. federal net operating loss carryforwards, or NOLs, of approximately $238.7 million, state NOLs of approximately $139.8 million, foreign NOLs of approximately $23.8 million, federal research and development tax credit carryforwards, or credit carryforwards, of approximately $10.2 million, state credit carryforwards of approximately $8.0 million, and foreign credit carryforwards of approximately $0.7 million. A lack of future taxable income would adversely affect our ability to utilize these NOLs and credit carryforwards. In addition, under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, or the Code, and comparable state income tax laws, a corporation that undergoes an "ownership change" is subject to limitations on its ability to utilize its NOLs and credit carryforwards to offset future taxable income following the ownership change. As a result, future changes in our stock ownership, including because of issuance of shares of common stock in connection with acquisitions or other direct or indirect changes in our ownership that may be outside of our control, could result in limitations on our ability to fully utilize our NOLs and credit carryforwards. The Company had an ownership change on December 31, 2015 subjecting the federal and state NOLs to an annual limitation. Additionally, the Company had an ownership change in January 2008 and $2.3 million of federal and state NOLs are already subject to limitation under Section 382 of the Code. Additionally, approximately $3.4 million of our federal NOLs and approximately $3.4 million of our state NOLs were generated during the pre-acquisition period by corporations that we acquired, and thus those NOLs already are subject to limitation under Section 382 of the Code and comparable state income tax laws. Also, depending on the level of our taxable income, all or a portion of our NOLs and credit carryforwards may expire unutilized, which could prevent us from offsetting any future taxable income we may generate by the entire amount of our current and future NOLs and credit carryforwards. We have recorded a full valuation allowance related to our NOLs, credit carryforwards, and other net deferred tax assets due to the uncertainty of the ultimate realization of the future benefits of those assets. To the extent we determine that all, or a portion of, our valuation allowance is no longer necessary, we will reverse the valuation allowance and recognize an income tax benefit in the reported financial statement earnings in that period. Once the valuation allowance is eliminated or reduced, its reversal will no longer be available to offset our current financial statement tax provision in future periods. Release of the valuation allowance would result in the recognition of certain net deferred tax assets and a decrease to income tax expense for the period the release is recorded. However, the exact timing and amount of the valuation allowance release are subject to change on the basis of the level of profitability that we are able to actually achieve.
We may require additional capital to support our business, and such capital might not be available on terms acceptable to us, if at all. Inability to obtain financing could limit our ability to conduct necessary operating activities and make strategic investments.
Various business challenges and opportunities may require additional funds, including the need to respond to competitive threats or market evolution by developing new solutions and improving our operating infrastructure through additional hiring or acquisition of complementary businesses or technologies, or both. In addition, we could incur significant expenses or shortfalls in anticipated cash generated as a result of unanticipated events in our business or competitive, regulatory, or other changes in our market, or longer payment cycles required or imposed by our buyers.
Our available cash and cash equivalents, any cash we may generate from operations, and our available line of credit under our credit facility may not be adequate to meet our capital needs, and therefore we may need to engage in equity or debt financings to secure additional funds. We may not be able to obtain additional financing on terms favorable to us, if at all. If we are unable to obtain adequate financing on terms satisfactory to us when we require it or are unable to renew our credit facility when it matures or enter into a new one, our ability to continue to support our business growth and respond to business challenges could be significantly impaired, and our business may be adversely affected.
If we do raise additional funds through future issuances of equity or convertible debt securities, our existing stockholders could suffer significant dilution, particularly due to the significant decline we have experienced in the market value of our common stock, and any new equity securities we issue could have rights, preferences and privileges superior to those of holders of our

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common stock. Any debt financing that we secure in the future could involve restrictive covenants relating to our capital raising activities and other financial and operational matters, including the ability to pay dividends. This may make it more difficult for us to obtain additional capital and to pursue business opportunities, including potential acquisitions. In addition, if we issue debt, the holders of that debt would have prior claims on the Company's assets, and in case of insolvency, the claims of creditors would be satisfied before distribution of value to equity holders, which would result in significant reduction or total loss of the value of our equity.
Our credit facility subjects us to operating restrictions and financial covenants that impose risk of default and may restrict our business and financing activities.
We have a $40.0 million credit facility with Silicon Valley Bank. At December 31, 2017, we had no amounts outstanding under this facility. Borrowings are secured by substantially all of our tangible personal property assets and all of our intangible assets are subject to a negative pledge in favor of Silicon Valley Bank. This credit facility is, and any replacement credit facility that we may secure will be, subject to certain covenants and borrowing conditions, including those related to financial ratios and liquidity. If we fail to perform in accordance with covenants or to satisfy conditions, we may not be able to make borrowings under the facility. The credit facility is, and any replacement credit facility that we may secure will be, also subject to restrictions that limit our ability, among other things, to:
dispose of or sell our assets;
make material changes in our business or management;
acquire, consolidate or merge with other entities;
incur additional indebtedness;
create liens on our assets;
pay dividends;
make investments;
enter into transactions with affiliates; and
pay off or redeem subordinated indebtedness.
These covenants may restrict our ability to finance our operations and to pursue our business activities and strategies. Our ability to comply with these covenants may be affected by events beyond our control. If a default were to occur and not be waived, such default could cause, among other remedies, all of the outstanding indebtedness under our loan and security agreement to become immediately due and payable. In such an event, our liquid assets might not be sufficient to meet our repayment obligations, and we might be forced to liquidate collateral assets at unfavorable prices or our assets may be foreclosed upon and sold at unfavorable valuations.
Our ability to renew our existing credit facility, which matures in September 2018, or to enter into a new credit facility to replace or supplement the existing facility may be limited due to various factors, including the status of our business, global credit market conditions, and perceptions of our business or industry by sources of financing. In particular, it may be difficult to renew or replace our existing credit facility if we are not able to produce, or demonstrate a path to produce, positive cash flow. In addition, if credit is available, lenders may seek more restrictive covenants and higher interest rates that may reduce our borrowing capacity, increase our costs, and reduce our operating flexibility.
If we make borrowings under the facility and do not have or are unable to generate sufficient cash available to repay our debt obligations when they become due and payable, either upon maturity or in the event of a default, we may not be able to obtain additional debt or equity financing on favorable terms, if at all. Our inability to obtain financing may negatively impact our ability to operate and continue our business as a going concern.
Risks Related to the Securities Markets and Ownership of our Common Stock
The price of our common stock has been and may continue to be volatile and the value of an investment in our common stock could decline.
Technology stocks have historically experienced high levels of volatility. The trading price of our common stock has fluctuated substantially and may continue to do so. These fluctuations could result in significant decreases in the value of an investment in our common stock. Factors that could cause fluctuations in the trading price of our common stock include the following:
announcements of new offerings, products, services or technologies, commercial relationships, acquisitions, or other events by us or our competitors;

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price and volume fluctuations in the overall stock market from time to time;
significant volatility in the market price and trading volume of technology companies in general and of companies in the digital advertising industry in particular;
fluctuations in the trading volume of our shares or the size of our public float;
actual or anticipated changes or fluctuations in our results of operations;
actual or anticipated changes in the expectations of investors or securities analysts, and whether our results of operations meet these expectations;
litigation involving us, our industry, or both;
regulatory developments in the United States, foreign countries, or both;
general economic conditions and trends;
major catastrophic events;
breaches or system outages;
departures of officers or other key employees; or
an adverse impact on the company resulting from other causes, including any of the other risks described in this report.
In addition, if the market for technology stocks or the stock market, in general, experiences a loss of investor confidence, the trading price of our common stock could decline for reasons unrelated to our business. The trading price of our common stock might also decline in reaction to events that affect other companies in our industry even if these events do not directly affect us. In the past, volatility in the market price of a company's securities has often resulted in securities litigation being brought against that company. Declines in the price of our common stock, even following increases, may result in securities litigation against us, which would result in substantial costs and divert our management's attention and resources from our business.
As a result of the significant decline we have experienced in the market value of our common stock, we no longer represent a permissible investment under the policies of some institutional investors. Further, our declining financial performance and lack of a clear path to growth and profitability make our stock an undesirable investment to many investors. As the pool of investors for our stock decreases, it becomes more difficult to attract the demand needed to support increases in the price of our stock.
Our equity compensation and acquisition practices expose our stockholders to dilution.
We have relied and may continue to rely heavily upon equity compensation, and consequently our outstanding unvested equity awards represent substantial dilution to our stockholders. In addition, we have used our common stock as consideration for acquisitions of other companies, and we may use shares of our common stock or securities convertible into our common stock from time to time in connection with financings, acquisitions, investments, or other transactions. Any such issuance could result in substantial dilution to our existing stockholders and cause the trading price of our common stock to decline. As of March 8, 2018, we had 50,254,718 shares of common stock outstanding, including 553,377 shares of unvested restricted stock issued under our various equity incentive plans. At that date, we also had outstanding under our equity incentive plans 5,999,451 unvested restricted stock units and 4,275,471 stock options, of which 2,833,999 were vested at a weighted-average exercise price of $10.16 per share and 1,441,472 were unvested. All of these outstanding stock awards, together with an additional 8,563,350 shares of our common stock reserved for issuance under our equity incentive plans and 1,781,853 shares of common stock reserved under our 2014 Employee Stock Purchase Plan, and certain future increases in the shares available pursuant to the plans' evergreen provisions (if applicable), are registered for offer and sale on Form S-8 under the Securities Act of 1933. We also intend to register the offer and sale of all other shares of common stock that may be authorized under our current or future equity compensation plans, issued under equity plans we may assume in acquisitions, or issued as inducement awards under New York Stock Exchange rules. Shares registered under these registration statements on Form S-8 will be available for sale in the public market subject to vesting arrangements and exercise of options, our Insider Trading Policy trading blackouts, and the restrictions of Rule 144 in the case of our affiliates.
Our public float is still relatively small, increasing the risk that sales by significant holders could adversely affect the market price for our stock.
The average daily trading volume for our common stock during 2017 was 700,050 shares. In addition, we are relatively new to the public markets and not well known to many analysts, investors, and others who could influence demand for our shares. Further, because we are a relatively small company without an established history of profitability, the range of investors willing to invest in our shares may be relatively limited. As a result of these factors, our shares can be susceptible to sudden, rapid declines in price, especially when large blocks of shares are sold. Under our Insider Trading Policy, we impose trading blackouts during the period beginning on or about the fifteenth day of the last month of each quarter and ending after two trading days following the

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filing of our next Quarterly Report on Form 10‑Q or Annual Report on Form 10-K. All of our employees are limited to selling their equity incentive plan shares during these open window periods. In addition, our employee restricted stock and restricted stock unit awards typically vest each May 15 and November 15, and are subject to automatic sale arrangements at those dates to cover taxes accruing on vesting. Finally, shares we issue as consideration for acquisitions may be subject to lock-up arrangements that expire in large numbers on certain dates. These insider trading windows, restricted stock vesting mechanics, and acquisition stock arrangements tend to concentrate selling into certain periods, and the resulting sales pressure can cause the trading price of our common stock to decline at those times. Sales of a substantial number of such shares, or the perception that such sales may occur, could cause our share price to fall or make it more difficult for investors to sell our common stock at a time and price that they deem appropriate, and could also impair our ability to raise capital through the sale of equity securities.
Competition for investors could adversely affect the price of our stock.
There are many companies in the advertising technology or "ad tech" space, but we are one of a relatively small portion of those companies that is publicly traded. Some of the other publicly traded ad tech companies are substantially larger than we are and have more diversified offerings, or may be perceived by investors as having greater stability or growth potential. Others may be focused on parts of the business that investors may view as more appealing. Ad tech or related advertising companies that are not yet public may become public, and publicly traded companies may enter the ad tech business through acquisitions. Increase in the number of publicly traded companies available to investors wishing to invest in ad tech may result in a decrease in demand for our shares, either because overall demand for ad tech investment does not increase commensurately with the increase in public companies in the ad tech space, or because we are not perceived as competitively differentiated or offering superior value compared to other such companies. Decrease in demand for our shares would result in suppressed growth, or decrease, in the value of our stock.
Our business could be negatively affected as a result of actions of activist stockholders.
Campaigns by stockholders to effect changes at publicly traded companies are sometimes led by investors seeking to increase short-term stockholder value through actions such as financial restructuring, increased debt, special dividends, stock repurchases or sales of assets or the entire company. The declines we have experienced in the market value of our common stock could increase the likelihood of an activist stockholder targeting our company. If we are targeted by an activist stockholder in the future, the process could be costly and time-consuming, disrupt our operations and divert the attention of management and our employees from executing our strategic plan. Additionally, perceived uncertainties as to our future direction as a result of stockholder activism or changes to the composition of our board of directors may lead to the perception of a change in the direction of our business, instability or lack of continuity, which may be exploited by our competitors, cause concern to current or potential buyers and sellers on our platform, who may choose to transact with our competitors instead of us, and make it more difficult to attract and retain qualified personnel.
If securities or industry analysts do not publish research or reports about our business, or publish inaccurate or unfavorable research or reports about our business, our share price and trading volume could decline.
The trading market for our common stock to some extent depends on the research and reports that securities or industry analysts publish about us. We do not control these analysts, and their reports or analyst consensus may not reflect our guidance, plans, or expectations. If one or more of the analysts who cover us downgrades our shares or expresses a negative opinion of our business prospects, our share price could decline. We have lost some analyst coverage as our financial performance has declined, and if we do not demonstrate revenue growth and a path to profitability, our remaining analysts may cease coverage. If one or more of these analysts decreases or ceases coverage of our company, we could lose visibility in the financial markets, which could cause our share price or trading volume to decline.
We do not intend to pay dividends for the foreseeable future and, consequently, investors' ability to achieve a return on their investment will depend on appreciation in the price of our common stock.
We have never declared or paid any dividends and we do not anticipate paying any cash dividends in the foreseeable future. In addition, our credit facility contains restrictions on our ability to pay dividends. As a result, investors may only receive a return on their investment in our common stock if the market price of our common stock increases.
Provisions of our charter documents and Delaware law may inhibit a potential acquisition of the company and limit the ability of stockholders to cause changes in company management.
Our amended and restated certificate of incorporation and amended and restated bylaws include provisions, as described below, that could delay or prevent a change in control of the company, and make it difficult for stockholders to elect directors who are not nominated by the current members of our board of directors or take other actions to change company management.

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Our certificate of incorporation gives our board of directors the authority to issue shares of preferred stock in one or more series, and to establish the number of shares in each series and to fix the price, designations, powers, preferences and relative, participating, optional or other rights, if any, and the qualifications, limitations, or restrictions of each series of the preferred stock without any further vote or action by stockholders. The issuance of shares of preferred stock may discourage, delay or prevent a merger or acquisition of the company by significantly diluting the ownership of a hostile acquirer, resulting in the loss of voting power and reduced ability to cause a takeover or effect other changes.
Our certificate of incorporation provides that our board of directors is classified, with only one of its three classes elected each year, and directors may be removed only for cause and only with the vote of 66 2/3% of the voting power of stock outstanding and entitled to vote thereon. Further, the number of directors is determined solely by our board of directors, and because we do not allow for cumulative voting rights, holders of a majority of shares of common stock entitled to vote may elect all of the directors standing for election. These provisions could delay the ability of stockholders to change the membership of a majority of our board of directors.
Under our bylaws, only the board of directors or a majority of remaining directors, even if less than a quorum, may fill vacancies resulting from an increase in the authorized number of directors or the resignation, death or removal of a director.
Our certificate of incorporation prohibits stockholder action by written consent, so any action by stockholders may only be taken at an annual or special meeting.
Our certificate of incorporation provides that a special meeting of stockholders may be called only by the board of directors. This could delay any effort by stockholders to force consideration of a proposal or to take action, including the removal of directors.
Under our bylaws, advance notice must be given to nominate directors or submit proposals for consideration at stockholders' meetings. This gives our board of directors time to defend against takeover attempts and could discourage or deter a potential acquirer from soliciting proxies or making proposals related to an unsolicited takeover attempt.
The provisions of our certificate of incorporation noted above may be amended only with the affirmative vote of holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of the company's voting stock, voting together as a single class. The same two-thirds vote is required to amend the provision of our certificate of incorporation imposing these supermajority voting requirements. Further, our bylaws may be amended only by our board of directors or by the same percentage vote of stockholders noted above as required to amend our certificate of incorporation. These supermajority voting requirements may inhibit the ability of a potential acquirer to effect such amendments to facilitate an unsolicited takeover attempt.
Our board of directors may amend our bylaws by majority vote. This could allow the board to use bylaw amendments to delay or prevent an unsolicited takeover, and limits the ability of an acquirer to amend the bylaws to facilitate an unsolicited takeover attempt.
We are also subject to Section 203 of the Delaware General Corporation Law, which prohibits us from engaging in any business combination with an interested stockholder for a period of three years from the date the person became an interested stockholder, unless certain conditions are met. These provisions make it more difficult for stockholders or potential acquirers to acquire the company without negotiation and may apply even if some of our stockholders consider the proposed transaction beneficial to them. For example, these provisions might discourage a potential acquisition proposal or tender offer, even if the acquisition proposal or tender offer were to be at a premium over the then-current market price for our common stock. These provisions could also limit the price that investors are willing to pay in the future for shares of our common stock.

Item 1B. Unresolved Staff Comments
None.

Item 2. Properties
Our corporate headquarters are located in Los Angeles, California, where we occupy facilities totaling approximately 47,000 square feet under a lease that expires in 2021. We use these facilities for our principal administration, sales and marketing, technology and development, and engineering activities. We also lease additional offices and maintain data centers in other locations in North American, South America, Europe, Australia, and Asia. We believe that our current facilities are adequate to meet

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our current needs, and that, if we require additional space, we will be able to obtain additional facilities on commercially reasonable terms.

Item 3. Legal Proceedings
We and our subsidiaries may from time to time be parties to legal or regulatory proceedings, lawsuits and other claims incident to our business activities and to our status as a public company. Such matters may include, among other things, assertions of contract breach or intellectual property infringement, claims for indemnity arising in the course of our business, regulatory investigations or enforcement proceedings, and claims by persons whose employment has been terminated. Such matters are subject to many uncertainties, and outcomes are not predictable with assurance. Consequently, we are unable to ascertain the ultimate aggregate amount of monetary liability, amounts which may be covered by insurance or recoverable from third parties, or the financial impact with respect to such matters as of December 31, 2017. However, based on our knowledge as of December 31, 2017, we believe that the final resolution of such matters pending at the time of this report, individually and in the aggregate, will not have a material adverse effect upon our consolidated financial position, results of operations or cash flows.
On March 31, 2017, Guardian News & Media Limited (Guardian) issued proceedings (the Complaint) against us in the Chancery Division of the High Court of Justice in England & Wales. The Complaint alleges that we underpaid Guardian for inventory sold by Guardian through our platform as a result of the fact that we charged fees to buyers of that inventory. Guardian claims we were precluded from charging buyer fees as a result of our contractual arrangements with Guardian and English agency law principles, as well as representations we allegedly made to Guardian. The Complaint claims damages including loss of revenue, interest, and costs, without specifying the amount of damages sought. We dispute Guardian’s claims and are defending them vigorously, but the Complaint involves disputed facts and complex legal questions, and its outcome is therefore uncertain. Even if Guardian were to prevail in this action, we do not believe our payment of the damages we think could be recoverable by Guardian would have a material adverse effect upon our consolidated financial position, results of operations, or cash flows. However, pending or in response to the outcome of this action, if we face similar claims from other clients or as a preventative measure, we might decide to provide concessions or make other changes to our business practices that could have such material adverse effects.

Item 4. Mine Safety Disclosures
Not applicable.


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PART II
Item 5. Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities
Our common stock has been listed on the New York Stock Exchange, or the NYSE, since April 1, 2014, under the symbol "RUBI". Prior to our initial public offering, or IPO, there was no public market for our common stock. The following table sets forth, for the indicated periods, the high and low sales prices of our common stock as reported on the NYSE.
 
 
High
 
Low
Fiscal 2016 Quarters Ended:
 
 
 
 
March 31, 2016
 
$
18.41

 
$
11.72

June 30, 2016
 
$
20.37

 
$
12.46

September 30, 2016
 
$
14.60

 
$
8.04

December 31, 2016
 
$
8.55

 
$
6.12

Fiscal 2017 Quarters Ended:
 
 
 
 
March 31, 2017
 
$
9.16

 
$
5.39

June 30, 2017
 
$
6.28

 
$
4.61

September 30, 2017
 
$
5.35

 
$
3.38

December 31, 2017
 
$
3.92

 
$
1.68

Holders of Record
As of March 8, 2018, there were approximately 86 holders of record of our common stock. The actual number of stockholders is greater than this number of record holders and includes stockholders who are beneficial owners but whose shares are held in street name by brokers and other nominees. This number of holders also does not include stockholders whose shares may be held in trust by other entities.
Dividend Policy
We have never declared or paid any dividends on our common stock, and we do not anticipate paying any cash dividends in the foreseeable future. We currently intend to retain any earnings to finance the operation and expansion of our business. Any future determination to pay dividends will be at the discretion of our board of directors and will be dependent upon then-existing conditions, including our earnings, capital requirements, results of operations, financial condition, business prospects and other factors that our board of directors considers relevant. See Item 7 "Management’s Discussion and Analysis of Financial Condition and Results of Operations" for additional information regarding our financial condition. In addition, our credit facility contains restrictions on our ability to pay dividends.
Purchases of Equity Securities by the Issuer and Affiliated Purchasers
We presently have no publicly announced repurchase plan or program.
Upon vesting of most restricted stock units or stock awards, we are required to deposit minimum statutory employee withholding taxes on behalf of the holders of the vested awards. As reimbursement for these tax deposits, we have the option to withhold from shares otherwise issuable upon vesting a portion of those shares with a fair market value equal to the amount of the deposits we paid. Withholding of shares in this manner is accounted for as a repurchase of common stock.
Common stock repurchases during the quarter ended December 31, 2017 were as follows (in thousands, except per share amounts):
Period
 
Total Number of Shares Purchased
 
Average Price Paid per Share
 
Total Number of Shares Purchased as Part of a Publicly Announced Program
 
Maximum Approximate Dollar Value that May Yet be Purchased Under the Program
October 1 – October 31, 2017
 
3

 
$
3.36

 

 
$

November 1 – November 30, 2017
 
159

 
$
1.89

 

 
$

December 1 – December 31, 2017
 

 
$

 

 
$


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Use of Proceeds
On April 7, 2014, we closed our IPO, whereby we sold 6,432,445 shares of common stock (including 1,015,649 shares sold pursuant to the underwriters' exercise of their over-allotment option), and the selling stockholders sold 1,354,199 shares of common stock. There has been no material change in the planned use of proceeds from our IPO as described in our final prospectus filed with the SEC on April 2, 2014 pursuant to Rule 424(b) of the Securities Act. 
Stock Performance Graph
This performance graph shall not be deemed "soliciting material" or to be "filed" with the SEC for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities under that Section, and shall not be deemed to be incorporated by reference into any filing of ours under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.
The following graph compares the cumulative total stockholder return on an initial investment of $100 in our common stock between April 1, 2014 (the date of our IPO) and December 31, 2017, with the comparative cumulative total returns of the S&P 500 Index, NYSE Composite Index, and NASDAQ Internet Total Return Index over the same period. As previously discussed, we have not paid any cash dividends and, therefore, the cumulative total return calculation for us is based solely upon stock price appreciation (depreciation) and not reinvestment of cash dividends, whereas the data for the S&P 500 Index, NYSE Composite Index, and NASDAQ Internet Total Return Index assumes reinvestments of dividends. The graph assumes our closing sales price on April 1, 2014 of $15.00 per share as the initial value of our common stock. The returns shown are based on historical results and are not necessarily indicative of, nor intended to forecast, future stock price.
http://api.tenkwizard.com/cgi/image?quest=1&rid=23&ipage=12130030&doc=13


Item 6. Selected Financial Data
The following selected consolidated financial data should be read in conjunction with Item 7 "Management's Discussion and Analysis of Financial Condition and Results of Operations" and our consolidated financial statements and the related notes appearing in Item 8. "Financial Statements and Supplementary Data" of this Annual Report on Form 10-K.

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The following table sets forth our selected consolidated historical financial data for the periods indicated. The consolidated statements of operations data for the years ended December 31, 2017, 2016 and 2015, and the consolidated balance sheet data as of December 31, 2017 and 2016 have been derived from our audited consolidated financial statements included elsewhere in this Annual Report on Form 10-K.
Our business has evolved significantly since our founding, including through acquisitions, and we expect the business to continue to evolve rapidly. Period-to-period comparisons of our historical results of operations are not necessarily meaningful, and historical operating results may not be indicative of future performance. See Note 7 to our consolidated financial statements for a discussion of the impacts of our recent acquisitions.
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
December 31, 2014
 
December 31, 2013
 
 
(in thousands, except per share data)
Revenue
 
$
155,545

 
$
278,221

 
$
248,484

 
$
125,295

 
$
83,830

Expenses:
 
 
 
 
 
 
 
 
 
 
Cost of revenue
 
56,836

 
73,247

 
58,495

 
20,754

 
15,358

Sales and marketing
 
51,794

 
83,328

 
83,333

 
43,203

 
25,811

Technology and development
 
47,500

 
51,184

 
42,055

 
22,718

 
18,615

General and administrative
 
55,596

 
68,570

 
70,199

 
57,398

 
27,926

Restructuring and other exit costs
 
5,959

 
3,316

 

 

 

Impairment of intangible assets and internal use software
 
4,585

 
23,473

 

 

 

Impairment of goodwill
 
90,251

 

 

 

 

Total expenses
 
312,521

 
303,118

 
254,082

 
144,073

 
87,710

Loss from operations
 
(156,976
)
 
(24,897
)
 
(5,598
)
 
(18,778
)
 
(3,880
)
Other (income) expense
 
(431
)
 
(1,984
)
 
(1,459
)
 
(277
)
 
5,122

Loss before income taxes
 
(156,545
)
 
(22,913
)
 
(4,139
)
 
(18,501
)
 
(9,002
)
Provision (benefit) for income taxes
 
(1,762
)
 
(4,860
)
 
(4,561
)
 
172

 
247

Net income (loss)
 
(154,783
)
 
(18,053
)
 
422

 
(18,673
)
 
(9,249
)
Cumulative preferred stock dividends(1)
 

 

 

 
(1,116
)
 
(4,244
)
Net income (loss) attributable to common stockholders
 
$
(154,783
)
 
$
(18,053
)
 
$
422

 
$
(19,789
)
 
$
(13,493
)
Net income (loss) per share attributable to common stockholders(2) (3):
 
 
 
 
 
 
 
 
 
 
Basic
 
$
(3.17
)
 
$
(0.39
)
 
$
0.01

 
$
(0.70
)
 
$
(1.17
)
Diluted
 
$
(3.17
)
 
$
(0.39
)
 
$
0.01

 
$
(0.70
)
 
$
(1.17
)
Weighted-average shares used to compute net income (loss) per share attributable to common stockholders(3):
 
 
 
 
 
 
 
 
 
 
Basic
 
48,869

 
46,655

 
39,663

 
28,217

 
11,488

Diluted
 
48,869

 
46,655

 
44,495

 
28,217

 
11,488

1. 
Upon the close of our IPO in April 2014, each outstanding share of convertible preferred stock was converted into one-half of a share of our common stock. Prior to the conversion, the holders of our convertible preferred stock were entitled to cumulative dividends prior and in preference to common stock. These cumulative preferred dividends are shown as a reduction to net income (loss) to arrive at net income (loss) attributable to common stockholders for the applicable periods above.
2. 
See Note 3 to our consolidated financial statements for a description of the method used to compute basic and diluted net income (loss) per share attributable to common stockholders.
3. 
All share, per-share and related information has been retroactively adjusted, where applicable, to reflect the impact of a 1-for-2 reverse stock split, including an adjustment to the preferred stock conversion ratio, which was effected on March 18, 2014.


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Consolidated Balance Sheet Data
 
 
As of December 31,
 
 
2017
 
2016
 
2015
 
2014
 
2013
 
 
(in thousands)
Cash and cash equivalents
 
$
76,642

 
$
149,423

 
$
116,499

 
$
97,196

 
$
29,956

Marketable securities, current and non-current
 
$
54,999

 
$
40,550

 
$
36,732

 
$

 
$

Accounts receivable, net
 
$
165,890

 
$
192,064

 
$
218,235

 
$
133,267

 
$
94,722

Property, equipment and internal use software development costs, net
 
$
60,127

 
$
52,768

 
$
39,332

 
$
26,697

 
$
15,916

Total assets
 
$
383,635

 
$
519,775

 
$
536,736

 
$
296,481

 
$
149,887

Debt and capital lease obligations, current and non-current
 
$

 
$

 
$

 
$
105

 
$
4,181

Total liabilities
 
$
219,024

 
$
220,262

 
$
258,635

 
$
167,729

 
$
133,727

Convertible preferred stock
 
$

 
$

 
$

 
$

 
$
52,571

Common stockholders' equity (deficit)
 
$
164,611

 
$
299,513

 
$
278,101

 
$
128,752

 
$
(36,411
)

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
You should read the following discussion and analysis of our financial condition and results of operations in conjunction with the consolidated financial statements and the related notes to those statements included in Item 8 to this Annual Report on Form 10-K. In addition to historical financial information, the following discussion contains forward-looking statements that reflect our plans, estimates, beliefs, and expectations and that involve risks and uncertainties. Our actual results and the timing of events could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to these differences include those discussed below and elsewhere in this Annual Report on Form 10-K, particularly in "Item 1A. Risk Factors" and the "Special Note About Forward-Looking Statements."

Overview
We provide a technology solution to automate the purchase and sale of digital advertising inventory for buyers and sellers. Our platform features applications and services for digital advertising inventory sellers, including websites, mobile applications, and other digital media properties, to sell their advertising inventory; applications and services for buyers, including advertisers, agencies, agency trading desks, demand side platforms, or DSPs, to buy advertising inventory; and a marketplace over which such transactions are executed. Together, these features power and enhance a comprehensive, transparent, independent advertising marketplace that brings buyers and sellers together and facilitates intelligent decision-making and automated transaction execution for the advertising inventory we manage on our platform. Our clients include many of the world’s leading publishers of websites and mobile applications and buyers of digital advertising inventory.
We measure buyer and seller activity on our platform through advertising spend, which we define as the buyer spending on advertising inventory transacted on our platform. From advertising spend we retain fees associated with the services that we provide, and those fees make up the revenue we record. Take rate is a measurement we use to track the level of our fees as a percentage of the advertising spend for a given period. We discuss advertising spend and take rate more fully in the “Non-GAAP Financial Measures and Operational Performance Measures” section below.

Industry Trends and Trends in Our Business
Market Opportunities
The programmatic digital advertising market continues to experience growth. In September 2017, MAGNA estimated that the global programmatic market (excluding search and social) will grow from $25 billion in 2017 to $51 billion by 2021. The compound annual growth rate for this market opportunity over that period is 19%. Over this same period, RTB spending as a percentage of total programmatic spending is expected to increase from 40% to 56%, or at a compound annual growth rate of 29%. Another important trend in the digital advertising industry is the continued expansion of automated buying and selling of advertising inventory through new and developing channels, including mobile, which has market growth rates exceeding those of the desktop channel and is a critical area of operational focus for us. According to MAGNA estimates, mobile advertising was an $11 billion global market in 2017 that is expected to increase to $32 billion by 2021, producing a compound annual growth rate of 31%.
While the industry is experiencing rapid growth in mobile, and while a portion of our mobile business is exceeding industry growth rates, our overall growth in mobile is below industry trends. Our mobile advertising spend increased $21.0 million, or 6%, for the year ended December 31, 2017, compared to the year ended December 31, 2016. Our slower growth in mobile relative to industry trends was driven by the composition of our mobile business, which consists of two components—mobile web and mobile applications. Initially, our growth in mobile was driven by mobile web, which is more similar to our desktop business. We were initially successful growing this business; however, by 2017, while it still composed more than half our mobile business, mobile web had begun to decline due to the same factors impacting our desktop business as described below. During this same time, however, our mobile application business, which is where we see the greatest potential for growth, has shown growth rates in excess of industry projections. For the fourth quarter of 2017, advertising spend from mobile applications composed more than half of our mobile business.
The growth of automated buying and selling of advertising inventory is also expanding into geographic markets outside of the United States, and in some markets, the adoption rate of programmatic digital advertising is greater than in the United States. We attribute advertising spend to the geographic location of the seller on whose inventory the advertising spend was directed. Our markets outside of the United States are more heavily built upon desktop display advertising than they are on mobile, and as such are subject to the same factors impacting our desktop business as described below. In addition, as programmatic advertising has grown in markets outside of the United States, we have seen more competitors enter those markets aggressively to gain market share. As a result of these factors, our mix of advertising spend in markets outside the United States declined to 35% from 37%

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during the years ending December 31, 2017 and 2016, respectively. Another factor impacting our business is that a large share of the growth in digital advertising spending worldwide is being captured by owned and operated sites, such as Facebook and Google.
Macro Trends Impacting Desktop
These market factors present long-term growth opportunities; however, in the near term the industry-wide shift from desktop to mobile advertising has had an adverse impact on our business. In recent years, we have seen an industry-wide slowdown in the growth rate for traditional desktop advertising, and the growth rate for this portion of the market is expected to flatten in future years. According to MAGNA, programmatic desktop advertising is expected to grow at a 6% compound annual growth rate over the 2017-2021 period. This results from the market shift to mobile channels. These trends are having a significant effect on our overall growth rate, because desktop advertising continues to be a significant part of our core business, representing 57% of advertising spend for the year ended December 31, 2017. Our advertising spend for desktop decreased 31% for the year ended December 31, 2017 compared to the year ended December 31, 2016. The effect of this overall shift away from traditional desktop display advertising was compounded for our business beginning in 2016 by the industry migration to header bidding, which occurred faster than we anticipated and while we were focused on other growth priorities. Header bidding increased competition for some inventory and resulted in adverse revenue effects for us due to loss to competitors of some inventory that we would otherwise have been able to sell through our platform. However, header bidding makes available to us significant amounts of inventory that previously we were unable to access and our header bidding solution began producing positive results for us in the second half of 2016, and gained significant traction in 2017. Header bidding is going through an additional technical evolution from the client side, which involves the browser running the auction, to a server-side solution, in which a server runs the auction and offers the potential for improved performance and speed. We believe that our investments in our client-side header bidding solution as well as server-side header bidding have the potential to improve our competitiveness in all markets in 2018 and beyond. However, we must continue to address certain technical and operational challenges, as described under "Item 1A. Risk Factors" in this Annual Report on Form 10-K, in order to realize our header bidding solution's full potential.
Because of these rapid developments in the industry, advertising spend from our traditional desktop business has declined and no longer can be relied upon to drive the growth of our business. Our strategic focus is on growth areas—including mobile, video, and PMPs—that are expected to represent a majority of our advertising spend in 2018. However, despite our solid progress in mobile, our traditional desktop business accounted for approximately 57% and 67% of our advertising spend for the years ending December 31, 2017 and 2016, respectively, and is expected to continue to represent a significant part of our business in the near term. Therefore, the weight of our desktop business and its decreasing advertising spend trend will continue to have a significant adverse effect on our growth until our advertising spend mix has shifted more fully to growth areas.
Take Rate Decline
Ad tech exchange intermediaries like us have used different revenue models in OMP transactions, including charging fees only to sellers or arbitraging the purchase and sale of ad impressions. Our approach was historically to charge fees to both buyers and sellers in OMP transactions conducted on our exchange, consistent with the fact that we provide services to each. Traditionally, for OMP waterfall transactions, we ran a modified second price auction in which the clearing price was the greater of the second highest bid in the auction plus one cent or the applicable price floor. Our buyer fees were determined algorithmically and added to the clearing price to determine the price charged to the winning bidder. Our take rate was made up of the total fees we charged buyers and sellers. In 2016, our take rate was 25.0%.
In 2017, we reduced and then eliminated our buyer fees as a result of three strategic moves we made in response to market conditions. First, in response to market demands for more efficiency and lower cost from intermediaries like us, and in an effort to be more competitive in attracting demand and capturing supply, we made a strategic decision to reduce the fees we charged buyers in OMP waterfall transactions.
Second, the mix of OMP transactions on our exchange shifted from approximately three quarters conducted through the traditional ad server waterfall at the end of December 2016 to approximately half through the ad server waterfall as of September 30, 2017. In traditional OMP waterfall transactions, available impressions are passed to different demand sources in a sequence determined by the seller’s ad server, and when an impression is passed to a particular demand source, that demand source is generally able to auction the impression with little or no competition. As the percentage of OMP waterfall transactions has declined, the percentage of header bidding transactions has increased. Header bidding increases competition for ad inventory by exposing impressions simultaneously to multiple sources of demand in a competitive auction that, if successful, replaces the ad server waterfall. Each demand source in a header bidding auction conducts its own auction for the impression and then passes its winning bid to a “downstream” meta-auction in which the seller evaluates bids from all its demand sources, and generally the highest bid wins. This competition pushes auction clearing prices much closer to the winning first-price bid than OMP waterfall transactions. In order to be more competitive and give our buyers a better chance of winning the header bidding impressions on which they bid, we began charging lower buyer fees for header bidding transactions so that we could pass higher priced bids into the downstream

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auction. Based upon experience with this approach and client feedback, in October 2017 we began offering a modified first price auction dynamic in our header bidding solution without buyer fees.
Third, as the ad tech industry has matured and evolved, competition has increased and pricing has become more transparent. The primary buyers in our OMP transactions are DSPs buying on behalf of agency and brand clients that are demanding reduced costs and fee transparency throughout the value chain. DSPs and their clients are consequently demanding that exchanges disclose and limit or eliminate buyer fees, and DSPs and their clients may reduce or eliminate spending on exchanges that charge buyer fees. In addition, some sellers believe that buyer fees ultimately reduce seller revenue, and therefore are seeking to cap or eliminate buyer fees on sale of their inventory. In response to these market trends, and consistent with our strategy to be a high volume, low cost and transparent exchange, we stopped charging our additive buyer fees altogether effective November 1, 2017. We still charge some buyers an access fee to connect to our system when their spending is too small to support the maintenance of their accounts, but these access fees in the aggregate are insignificant. As such, our future revenue will consist almost entirely of a unitary marketplace fee. Most of our marketplace fees are negotiated with sellers as a percentage of the auction clearing price for sale of their inventory. In some cases, we reduce the buyer’s bid amount by the amount of our fee and pass the remainder as the bid to the seller. If the bid wins we retain the amount of the bid reduction as our fee. We do this at the discretion of sellers that allocate advertising inventory through a decisioning process that follows after our auction and incorporates other demand sources as well as our bids, and that prefer or require that we submit our bids to them net of our fees, so that our bid matches the amount we will owe them if we win. This is referred to as net bidding. Net bidding amounts can vary across transactions depending upon various factors including inventory and auction characteristics and seller policies. In general, we believe the marketplace fees we earn in these transactions are consistent with or below market rates for comparable transactions.
These strategic price reductions contributed to the decrease in our take rate from 25.0% for 2016 to 12.8% for the fourth quarter of 2017 (which includes fees on OMP waterfall transactions and some header bidding transactions in October but not November or December). Our take rate as we exited 2017, which did not include any buyer fees, was approximately 11.6%.
Our strategic pricing reductions are intended to address the market's demand for lower costs and to attract more inventory and spending to our platform. Lower pricing has caused our revenue and margins to decline significantly. In order to adjust to our lower take rates and return to growth, we must increase advertising spend on our platform. Increases in PMP and header bidding transactions as a percentage of the activity on our exchange could yield higher advertising spend despite lower take rates due to higher CPMs typically associated with PMP transactions, and from modified first-price auctions in header bidding transactions. However, in an increasingly competitive market in which buyers and sellers have many choices, it is not clear whether pricing reductions will result in increases in spending on our platform, or whether any spending increases will compensate fully for the reduction in pricing. Further, because the rate at which we win header bidding auctions is much lower, due to competition inherent in header bidding transactions, than the rate at which we win waterfall transactions, as our business continues to shift away from waterfall transactions to header bidding, we need to participate in far more header bidding auctions to compensate for the decline in the number of waterfall transactions. Driving revenue growth in this situation is difficult to accomplish in a competitive market and requires accessing significantly greater inventory levels from our sellers and in turn processing more auctions. This growth in business volume requires adequate processing capacity as well as ongoing innovation to address evolving client needs and capture business.
Prior to the elimination of buyer fees, such fees represented approximately half of our revenue for the first ten months of 2017, and we do not expect to be able to grow advertising spending or reduce costs quickly enough in the near term to make up for the elimination of these fees. This will result in significant cash consumption to support operations during 2018. Unless and until we are able to compensate for elimination of our buyer fees by increasing advertising spending on our platform, through higher transaction volumes or higher transaction values or both, we will not be able to grow our business and our cash resources will diminish. 
Therefore, while we work to increase the volume of transactions on our exchange and compete more effectively, we must operate more efficiently to relieve the pressure on our margins and cash resources that has resulted from our price reductions and to compensate for the ongoing investments in technology and data processing capabilities required to support the increased volume of transactions that our growth plans require. Consequently, we are pursuing various cost-control and efficiency initiatives. As part of these efforts, during the first quarter of 2018 we undertook measures to reduce headcount by approximately 100 people, or 19% of our workforce, and to reduce other operating costs. Our actions include reductions in administrative staff to bring our general and administrative operations into better alignment with the current size of the business as well as in sales and technical personnel as a result of offshoring certain development functions, organizational delayering and restructuring, and reducing investment in unprofitable projects. we also continue to pursue increased automation and efficiency across all aspects of the company. See Item 1. Business Overview - "Recent Developments” for more information.


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Components of Our Results of Operations
We report our financial results as one operating segment. Our consolidated operating results, together with non-GAAP financial measures and the operational performance measures, are regularly reviewed by our chief operating decision maker, principally to make decisions about how we allocate our resources and to measure our consolidated operating performance.
Revenue
We generate revenue from the purchase and sale of our digital advertising inventory through our marketplace. We recognize revenue upon the fulfillment of our contractual obligations in connection with a completed transaction, subject to satisfying all other revenue recognition criteria. Our revenue recognition policies are discussed in more detail within "Critical Accounting Policies" and in Note 2 "Organization and Summary of Significant Accounting Policies" of the accompanying Notes to the Consolidated Financial Statements.
Expenses
We classify our expenses into the following categories:
Cost of Revenue. Our cost of revenue consists primarily of data center costs, bandwidth costs, depreciation and maintenance expense of hardware supporting our revenue-producing platform, amortization of software costs for the development of our revenue-producing platform, amortization expense associated with acquired developed technologies, personnel costs, facilities-related costs, and for transactions we have previously reported on a gross basis, the amounts we paid sellers. Personnel costs included in cost of revenue include salaries, bonuses, stock-based compensation, and employee benefit costs, and are primarily attributable to personnel in our network operations group who support our platform. We capitalize costs associated with software that is developed or obtained for internal use and amortize the costs associated with our revenue-producing platform in cost of revenue over their estimated useful lives. We amortize acquired developed technologies over their estimated useful lives.
Sales and Marketing. Our sales and marketing expenses consist primarily of personnel costs, including stock-based compensation and the sales bonuses paid to our sales organization, as well as marketing expenses such as brand marketing, travel expenses, trade shows and marketing materials, professional services, and amortization expense associated with client relationships and backlog from our business acquisitions, and to a lesser extent, facilities-related costs and depreciation and amortization. Our sales organization focuses on increasing the adoption of our solution by existing and new buyers and sellers. We amortize acquired intangibles associated with client relationships and backlog from our business acquisitions over their estimated useful lives.
Technology and Development. Our technology and development expenses consist primarily of personnel costs, including stock-based compensation and bonuses, as well as professional services associated with the ongoing development and maintenance of our solution, and to a lesser extent, facilities-related costs and depreciation and amortization, including amortization expense associated with acquired intangible assets from our business acquisitions that are related to technology and development functions. These expenses include costs incurred in the development, implementation, and maintenance of internal use software, including platform and related infrastructure. Technology and development costs are expensed as incurred, except to the extent that such costs are associated with internal use software development that qualifies for capitalization, which are then recorded as internal use software development costs, net, on our consolidated balance sheet. We amortize internal use software development costs that relate to our revenue-producing activities on our platform to cost of revenue and amortize other internal use software development costs to technology and development costs or general and administrative expenses, depending on the nature of the related project. We amortize acquired intangibles associated with technology and development functions from our business acquisitions over their estimated useful lives.
General and Administrative. Our general and administrative expenses consist primarily of personnel costs, including stock-based compensation and bonuses, associated with our executive, finance, legal, human resources, compliance, and other administrative personnel, as well as accounting and legal professional services fees, facilities-related costs and depreciation, and other corporate-related expenses. General and administrative expenses also include amortization of internal use software development costs and acquired intangible assets from our business acquisitions over their estimated useful lives that relate to general and administrative functions and changes in fair value associated with the liability-classified contingent consideration related to acquisitions.
Restructuring and Other Exit Costs. Our restructuring and other exit costs are cash and non-cash charges consisting primarily of employee termination costs and facility closure costs.
Impairment of Intangible Assets and Internal Use Software. Our impairment charges are non-cash charges related to our intangible assets and internal use software. Certain events or changing circumstances that impact the value of our intangible assets may necessitate a valuation analysis, as described within "Critical Accounting Policies" and in Note 2 "Organization and Summary

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of Significant Accounting Policies" of the accompanying Notes to the Consolidated Financial Statements. If needed, an impairment is recorded to reduce the carrying amount of the assets to their estimated fair value in the period that the valuation analysis is performed.
Impairment of Goodwill. Goodwill impairment charges are non-cash expenses recognized to reduce the goodwill asset on our balance sheet. Certain events or changing circumstances that impact the value of our business may necessitate a valuation analysis, as described within "Critical Accounting Policies" and in Note 2 "Organization and Summary of Significant Accounting Policies" of the accompanying Notes to the Consolidated Financial Statements. If the estimated fair value of the Company is lower than its carrying amount, a goodwill impairment is recognized for the difference, up to the carrying amount of goodwill.
Other (Income), Expense
Interest (Income) Expense, Net. Interest expense is mainly related to our credit facility. Interest income consists of interest earned on our cash equivalents and marketable securities and was insignificant for the years ended December 31, 2017, 2016 and 2015.
Other Income. Other income consists primarily of rental income from commercial office space we hold under lease and have sublet to other tenants.
Foreign Currency Exchange (Gain) Loss, Net. Foreign currency exchange (gain) loss, net consists of gains and losses on foreign currency transactions. We have foreign currency exposure related to our accounts receivable and accounts payable that are denominated in currencies other than the U.S. Dollar, principally the British Pound.
Provision (Benefit) for Income Taxes
Provision (benefit) for income taxes consists of federal, state, and foreign income taxes and is primarily the result of the deferred tax liability associated with the nToggle acquisition.
On December 22, 2017, the U.S. government enacted the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act includes significant changes to the U.S. corporate income tax system including: a federal corporate rate reduction from 34% to 21%; limitations on the deductibility of executive compensation and research and development (“R&D”) expenditures, immediate expensing of qualified property, the creation of new minimum taxes such as the base erosion anti-abuse tax (“BEAT”) and Global Intangible Low Taxed Income (“GILTI”) tax; and the transition of U.S. international taxation from a worldwide tax system to a modified territorial tax system, which will result in a one time U.S. tax liability on those earning which have not previously been repatriated to the U.S. (the “Transition Tax”).
The Tax Act imposes a Transition Tax on previously untaxed accumulated and current earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, we determined, among other things, the amount of post-1986 E&P of the relevant subsidiaries.
The Tax Act allows for the immediate write off (“expensing”) of the cost of qualified property acquired and placed in service after September 27, 2017 and before January 1, 2023. Following January 1, 2023, the expensing phases down 20% annually through January 1, 2027.
Additionally, the Tax Act imposes a new BEAT, essentially a 10% minimum tax (5% for tax years beginning after December 31, 2017, increasing to 10% for years beginning after December 31, 2018) calculated on a base equal to taxpayer’s income determined without tax benefits arising from base erosion payments and, also, requires certain GILTI income earned by controlled foreign corporations (“CFCs”) to be included in the gross income of the CFCs’ U.S. shareholder (for tax years beginning after December 31, 2017). GAAP allows us to either (i) treat taxes due on future U.S. inclusions in taxable income related to BEAT and GILTI as current-period expense when incurred (the “period cost method”); or (ii) factor such amounts into our measurement of deferred taxes (the “deferred method”). We elected the period cost method. Given that these new rules are not yet effective, we have not made any adjustments to our financial statements for these items for the year ended December 31, 2017.
Due to uncertainty as to the realization of benefits from the predominant portion of our domestic and international net deferred tax assets, including net operating loss carryforwards and research and development tax credits, we have a full valuation allowance reserved against such net deferred tax assets. We intend to continue to maintain a full valuation allowance on our deferred tax assets until there is sufficient evidence to support the reversal of all or some portion of these allowances. Release of the valuation allowance would result in the recognition of certain net deferred tax assets and a decrease to income tax expense or recognition of a benefit for the period the release is recorded. However, the exact timing and amount of the valuation allowance release are subject to change on the basis of the level of profitability that we are able to achieve.

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Pursuant to Section 382 of the Internal Revenue Code, we underwent an ownership change for tax purposes (i.e., a more than 50% change in stock ownership in aggregated 5% shareholders) on December 31, 2015. As a result, the use of our domestic NOL carryforwards and tax credits generated prior to the ownership change will be subject to the annual 382 use limitations of approximately $53.1 million. We have concluded that the ownership change will not impact our ability to utilize substantially all of our NOLs and carryforward credits to the extent we generate taxable income that can be offset by such losses.


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Results of Operations
The following tables set forth our consolidated results of operations for the periods presented.
 
 
Year Ended
 
Favorable/(Unfavorable) %
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
2017 vs 2016
 
2016 vs 2015
 
 
(Dollars in thousands)
 
 
 
 
Revenue
 
$
155,545

 
$
278,221

 
$
248,484

 
(44
)%
 
12
 %
Expenses:
 
 
 
 
 
 
 
 
 


Cost of revenue(1)(2)
 
56,836

 
73,247

 
58,495

 
22
 %
 
(25
)%
Sales and marketing(1)(2)
 
51,794

 
83,328

 
83,333

 
38
 %
 
 %
Technology and development(1)(2)
 
47,500

 
51,184

 
42,055

 
7
 %
 
(22
)%
General and administrative(1)(2)
 
55,596

 
68,570

 
70,199

 
19
 %
 
2
 %
Restructuring and other exit costs
 
5,959

 
3,316

 

 
(80
)%
 
NM

Impairment of intangible assets and internal use software
 
4,585

 
23,473

 

 
80
 %
 
NM

Impairment of goodwill
 
90,251

 

 

 
NM

 
NM

Total expenses
 
312,521

 
303,118

 
254,082

 
(3
)%
 
(19
)%
Loss from operations
 
(156,976
)
 
(24,897
)
 
(5,598
)
 
NM

 
NM

Other income
 
(431
)
 
(1,984
)
 
(1,459
)
 
(78
)%
 
36
 %
Loss before income taxes
 
(156,545
)
 
(22,913
)
 
(4,139
)
 
NM

 
NM

Benefit for income taxes
 
(1,762
)
 
(4,860
)
 
(4,561
)
 
(64
)%
 
7
 %
Net income (loss)
 
$
(154,783
)
 
$
(18,053
)
 
$
422

 
NM

 
NM

NM - Not meaningful
(1) 
Stock-based compensation expense included in our expenses was as follows:
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Cost of revenue
 
$
404

 
$
344

 
$
240

Sales and marketing
 
4,582

 
8,520

 
7,415

Technology and development
 
4,034

 
5,788

 
4,963

General and administrative
 
9,924

 
14,042

 
17,966

Restructuring and other exit costs
 
1,560

 

 

Total stock-based compensation expense
 
$
20,504

 
$
28,694

 
$
30,584

(2) 
Depreciation and amortization expense included in our expenses was as follows:
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Cost of revenue
 
$
31,981

 
$
28,853

 
$
19,290

Sales and marketing
 
1,066

 
9,020

 
8,168

Technology and development
 
1,957

 
2,759

 
1,815

General and administrative
 
1,221

 
2,131

 
1,737

Total depreciation and amortization expense
 
$
36,225

 
$
42,763

 
$
31,010


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The following table sets forth our consolidated results of operations as a percentage of our revenue for those periods presented:
 
 
Year Ended *
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
Revenue
 
100
 %
 
100
 %
 
100
 %
Cost of revenue
 
37

 
26

 
24

Sales and marketing
 
33

 
30

 
34

Technology and development
 
31

 
18

 
17

General and administrative
 
36

 
25

 
28

Restructuring and other exit costs
 
4

 
1

 

Impairment of intangible assets and internal use software
 
3

 
8

 

Impairment of goodwill
 
58

 

 

Total expenses
 
201

 
109

 
102

Loss from operations
 
(101
)
 
(9
)
 
(2
)
Other income, net
 

 
(1
)
 
(1
)
Loss before income taxes
 
(101
)
 
(8
)
 
(2
)
Benefit for income taxes
 
(1
)
 
(2
)
 
(2
)
Net loss
 
(100
)%
 
(6
)%
 
 %
Comparison of the Years Ended December 31, 2017, 2016 and 2015
Revenue
Revenue decreased $122.7 million, or 44%, for the year ended December 31, 2017 compared to the year ended December 31, 2016. The decrease is due to a decrease in advertising spend on our platform due to market and competitive pressures, decrease in traditional desktop display spending, and header bidding dynamics as described above. In addition, we implemented certain strategic reductions in our pricing in response to our perception of market conditions and in an effort to increase our competitiveness. Year-over-year revenue was also adversely affected by shifts in our business mix in favor of buyers and sellers and inventory types with lower fee rates. Finally, the decline of our intent marketing solution and its ultimate cessation in the first quarter of 2017 contributed to the total revenue decrease when compared to the prior year. Our average CPM was $1.43 for the year ended December 31, 2017 compared to $1.25 for the prior year period. The increase of $0.18, or 14%, in CPM was due to a shift in the mix of our business from waterfall to header bidding transactions, with the latter generating higher CPMs due to the more competitive nature of that business as noted above. In addition, average CPM increased during the period due to a shift in mix of transactions on our platform from lower-priced, higher-volume transactions mainly associated with static bidding to higher-priced, lower-volume transactions mainly associated with RTB. We ceased offering our static bidding offering after the third quarter of 2016. The increase in average CPM was partially offset by a decrease in paid impressions from 819 billion for the year ended December 31, 2016 to 585 billion for the year ended December 31, 2017. The decrease in paid impressions resulted from a shift in mix of ad requests, which in 2017 included a higher proportion of those generated from sellers via header bidding compared to those generated via waterfall. As noted above, header bidding makes available to us significant amounts of inventory that previously we were unable to access; however, due to the competitive nature of header bidding, the rate at which we win those auctions and convert that inventory to paid impressions is much lower than the rate at which we win waterfall auctions, resulting in fewer paid impressions. In addition, the mix shift noted above from static bidding to RTB after the third quarter of 2016 contributed to lower paid impressions in 2017.
Revenue increased $29.7 million, or 12%, for the year ended December 31, 2016 compared to the year ended December 31, 2015. The increase in 2016 revenue was primarily due to an increase in the amount of advertising spend on our platform during the year ended December 31, 2016 compared to the year ended December 31, 2015. The increase in revenue was also attributable to an increase in average CPM to $1.25 for the year ended December 31, 2016 from $1.09 for the year ended December 31, 2015, an increase of $0.16, or 15%. This increase in average CPM during the period was due to increased matching efficiency and a shift in mix of transactions on our platform from lower-priced higher-volume inventory mainly associated with static bidding to higher-priced lower-volume inventory mainly associated with RTB. The increase in average CPM was partially offset by a decrease in paid impressions resulting from the same shift in mix of transactions on our platform from static bidding to RTB. While paid impressions associated with RTB increased during the year ended December 31, 2016 compared to the year ended December 31, 2015, paid impressions associated with static bidding decreased, resulting in an overall decrease of 11% from 920 billion for the year ended December 31, 2015 to 819 billion for the year ended December 31, 2016.

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Revenue is impacted by shifts in the mix of advertising spend by transaction type and channel, changes in the fees we charge buyers and sellers for our services (which drive take rate), and other factors such as changes in the market, our execution of the business, and competition. Industry dynamics are challenging due to market and competitive pressures and make it difficult to predict the near-term effect of our growth initiatives. Consequently, while we anticipate long-term benefits from these initiatives, in 2017 we experienced a decrease in revenue compared to 2016 resulting from the cessation of our intent marketing solution, a decreasing overall take rate (partially due to our elimination of buyer fees in late 2017), increased competition for inventory partially due to continued industry-wide growth in header bidding, and increased competition for demand, including from large providers of owned and operated inventory. Most of the strategic pricing reductions we implemented in the first half of the year did not take effect until part way through the second quarter, and elimination of our buyer fees did not take effect until November 1, 2017, so our pricing reductions had a more significant effect on the second half of the year, and will impact 2018 more significantly on a full year basis unless counterbalanced by positive effects from these reductions or other growth initiatives. Our take rate was 18.5% for the year ended December 31, 2017 compared to 25.0% the prior year, and will continue to decline due to the elimination of our buyer transaction fees on November 1, 2017. The take rate was 12.8% for the fourth quarter of 2017, and it was 11.6% in December 2017. In addition to the elimination of buyer transaction fees resulting in lower take rate, an increase in PMP transactions as a percentage of the transactions on our platform could contribute to lower take rates because PMP transactions can carry slightly lower fees than OMP transactions. Unless and until we are able to compensate for the reduction in our fees by increasing advertising spend on our platform, through higher transaction volumes or higher transaction values or both, or by increasing seller fees, our revenue will continue to decline, we will not be able to grow our business, and our cash resources may be depleted.
Cost of Revenue
Cost of revenue decreased by $16.4 million, or 22%, for the year ended December 31, 2017 compared to the year ended December 31, 2016, primarily due to a decrease of $20.0 million in the amounts we paid sellers related to transactions reported on a gross basis associated with our intent marketing solution, which we discontinued during the quarter ended March 31, 2017. These decreases were partially offset by an increase of $3.1 million in depreciation and amortization expense as a result of additional computer equipment and network hardware, and capitalized internal use software, as we continued to enhance the functionality of our existing products and build new solutions to expand our offerings. Despite the decrease in total expenditures, cost of revenue as a percent of revenue increased from 26% to 37% as a result of lower revenue in the year ended December 31, 2017 compared to the year ended December 31, 2016, driven by the lower take rate and lower advertising spend noted above.
Cost of revenue increased by $14.8 million, or 25%, for the year ended December 31, 2016 compared to the year ended December 31, 2015. This increase was primarily due to an increase of $9.6 million in depreciation and amortization expense, an increase in data center, hosting, and bandwidth costs of $2.5 million, and an increase in personnel costs of $1.2 million. The increase in depreciation and amortization was primarily attributable to an increase in amortization of developed technology acquired in our business combinations, depreciation of computer equipment and network hardware, and amortization of capitalized internal use software, as we continued to functionally enhance our existing products, as well as build new solutions to expand our offerings. The amortization of developed technology acquired in our business combinations reflected in cost of revenue was $9.5 million and $6.3 million for the years ended December 31, 2016 and 2015, respectively. The amortization of capitalized internal use software reflected in cost of revenue was $8.0 million and $6.5 million for the years ended December 31, 2016 and 2015, respectively. The increases in data center, hosting, and bandwidth costs were primarily to support the increase in the use of our platform and international expansion efforts requiring additional data centers, hardware, software, and maintenance expenses. Cost of revenue in 2016 also included an increase of $1.0 million in amounts we paid sellers, reflecting the impact of a full year of gross revenue reporting for our intent marketing business following the acquisition of Chango in April 2015, as discussed earlier.
We expect cost of revenue to be higher in absolute dollars in 2018 compared to 2017. We expect to have increased spending on data centers and investments in developed technology to support our strategic growth initiatives and the auction processing costs and infrastructure required to process greater volumes of data and transactions we will need to grow revenue. Cost of revenue may fluctuate from quarter to quarter and period to period, on an absolute dollar basis and as a percentage of revenue, depending on revenue levels and the volume of transactions we process supporting those revenues, and the timing and amounts of investments.
Sales and Marketing
Sales and marketing expense decreased by $31.5 million, or 38%, for the year ended December 31, 2017 compared to the year ended December 31, 2016, primarily due to a decrease of $18.2 million in sales and marketing personnel costs as a result of our operating cost control initiatives. Additionally, sales and marketing depreciation and amortization costs decreased by $8.0 million primarily due to lower amortization of acquired client relationships.
Sales and marketing expenses remained consistent at $83.3 million for the years ended December 31, 2016 and 2015, with no significant fluctuations.

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We expect sales and marketing expenses to decline in 2018 compared to 2017 as a result of headcount reductions we implemented in the first quarter of 2018, as described above. Sales and marketing expense may fluctuate quarter to quarter and period to period, on an absolute dollar basis and as a percentage of revenue, based on revenue levels, the timing of our investments and seasonality in our industry and business.
Technology and Development
Technology and development expense decreased by $3.7 million, or 7%, for the year ended December 31, 2017 compared to the year ended December 31, 2016 primarily due to a decrease in headcount and related personnel costs of $3.8 million as a result of our operating cost control initiatives. In addition, technology related depreciation and amortization decreased $0.8 million compared to the prior year period due to fixed and intangible assets reaching their full useful lives. These decreases were partially offset by an increase of $1.7 million in software licenses due to annual increases in our existing licenses to maintain and support our technology and development efforts.
Technology and development expense increased by $9.1 million, or 22%, for the year ended December 31, 2016 compared to the year ended December 31, 2015, primarily due to an increase in personnel costs of $4.5 million resulting from an increase in headcount as a result of continued hiring of engineers to maintain and support our technology and development efforts.
We expect technology and development expense to decline in 2018 compared to 2017 as a result of headcount reductions we implemented in the first quarter 2018, as described above, and we expect additional savings in 2018 as we improve our efficiencies in technology development while continuing to invest in our engineering and technology teams. The timing and amount of our capitalized development and enhancement projects may affect the amount of development costs expensed in any given period. As a percentage of revenue, technology and development expense may fluctuate from quarter to quarter and period to period based on revenue levels, the timing and amounts of these investments, the timing and the rate of the amortization of capitalized projects and the timing and amounts of future capitalized internal use software development costs.
    General and Administrative
General and administrative expense decreased by $13.0 million, or 19%, for the year ended December 31, 2017 compared to the year ended December 31, 2016, primarily due to a decrease in headcount and related personnel costs of $9.5 million as a result of our cost control initiatives. In addition, professional services costs decreased by $1.8 million primarily due to decreased legal and consulting costs.
General and administrative expense decreased by $1.6 million, or 2%, for the year ended December 31, 2016 compared to the year ended December 31, 2015, primarily due to a decrease in personnel costs of $2.3 million, a decrease in professional services costs of $0.5 million, partially offset by increases of $0.4 million in depreciation and amortization, $0.7 million in insurance and taxes, and $0.5 million in software license costs. The decrease in personnel costs was primarily due to decreased headcount. The decrease in professional services was primarily due to decreased transaction related services. The increase in depreciation and amortization was mainly related to amortization of non-compete agreements and trademarks acquired in our business combinations. As a percentage of revenue, general and administrative expenses decreased for the year ended December 31, 2016 compared to the year ended December 31, 2015 primarily as a result of revenue increasing at a higher percentage compared to the increase in general and administrative expenses.
We expect quarterly general and administrative expense to decline in 2018 compared to 2017 as a result of headcount reductions we implemented in the first quarter 2018, as described above. General and administrative expenses may fluctuate from quarter to quarter and period to period based on the timing and amounts of our investments and related expenditures in our general and administrative functions as they vary in scope and scale over periods which may not be directly proportional to changes in revenue.
Restructuring and Other Exit Costs
In November 2016, we announced that we would cease providing intent marketing services and planned to close our Toronto office. This plan resulted in an initial workforce reduction of approximately 125 employees. We continued to realign our organization, including our management team, to a more cost efficient structure in the first half of 2017.
In connection with these activities, we recorded restructuring and other exit costs of $6.0 million and $3.3 million during the years ended December 31, 2017 and 2016, respectively, primarily for one-time employee termination benefits. The costs incurred included $4.4 million and $3.3 million in cash expenditures, of which $5.1 million and $2.5 million were paid in 2017 and 2016, respectively. The remaining liability as of December 31, 2017 will be paid in the first quarter of 2018.


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As of December 31, 2017, we estimate the annualized cash basis cost savings related to the headcount reductions made in late 2016 and the first half of 2017 will be approximately $18.0 million, which we began to realize in the second quarter of 2017. Some of these cost savings may be offset by additional resources we may determine are necessary to support the strategic growth of our business.
As part of our on-going evaluation of efficiency and implementation of cost-control measures, during the first quarter of 2018 we undertook measures to reduce headcount by approximately 100 people, or 19% of our workforce, and to reduce other operating costs. Our actions include reductions in administrative staff to bring our general and administrative operations into better alignment with the current size of the business as well as in sales and technical personnel as a result of offshoring certain development functions, organizational delayering and restructuring, and reducing investment in unprofitable projects. We estimate the 2018 restructuring activities will result in annualized cash basis cost savings of approximately $24.0 million, which we will begin to realize in the third quarter of 2018.
Impairment of Intangible Assets and Internal Use Software
In the fourth quarter of 2017, we recognized an impairment charge for the remaining intangible assets and internal use software associated with our Guaranteed Orders platform, totaling $4.6 million. These intangible assets included developed technology, customer relationships, and internal use software acquired as part of an acquisition completed in 2014.    
In December 2016, we made the decision to cease providing intent marketing services, which was announced in January 2017. In connection with this decision, we assessed the value of the asset group related to the intent marketing services, which consisted of customer relationships and developed technology, and determined that the asset group was impaired. Accordingly, we recorded a charge for the impairment of intangible assets totaling $23.5 million, which is included in the consolidated statement of operations for the year ended December 31, 2016.
Impairment of Goodwill
In the third quarter of 2017, we revised future cash flow projections as part of our goodwill impairment analysis (as discussed in Note 9 "Fair Value Measurements" in the accompanying Notes to Consolidated Financial Statements). One of the significant changes was the impact of our strategic decision to reduce, and ultimately eliminate, buyer transaction fees. Based on the updated goodwill impairment analysis performed, we determined that our goodwill was impaired and recorded a $90.3 million impairment charge, to write off the entire goodwill balance. There was no impairment of goodwill recorded for the years ended December 31, 2016 and 2015.
Other (Income) Expense, Net
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Interest income, net
 
$
(908
)
 
$
(491
)
 
$
(59
)
Other income
 
(688
)
 
(554
)
 

Foreign exchange (gain) loss, net
 
1,165

 
(939
)
 
(1,400
)
Total other income, net
 
$
(431
)
 
$
(1,984
)
 
$
(1,459
)
Other income primarily consists of income generated by our sub-leasing activity.
Foreign exchange (gain) loss, net is impacted by movements in exchange rates, primarily the British Pound and Euro relative to the U.S. Dollar, and the amount of foreign-currency denominated receivables and payables, which are impacted by our billings to buyers and payments to sellers. The foreign currency gains, net during the year ended December 31, 2017, 2016 and 2015, respectively, were primarily attributable to the strengthening of the U.S. Dollar in relation to the British Pound and Euro for foreign currency denominated transactions.
Provision (Benefit) for Income Taxes     
We recorded an income tax benefit for the years ended December 31, 2017, 2016 and 2015 of $1.8 million, $4.9 million, and $4.6 million, respectively. The tax benefit for the year ended December 31, 2017 is primarily the result of the deferred tax liability associated with the nToggle acquisition.
On December 22, 2017, the U.S. government enacted the Tax Act. The Tax Act includes significant changes to the U.S. corporate income tax system including: a federal corporate rate reduction from 34% to 21%; limitations on the deductibility of

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executive compensation and R&D expenditures, immediate expensing of qualified property, the creation of new minimum taxes such as the BEAT tax and GILTI tax; and the Transition Tax.
The Tax Act imposes a Transition Tax on previously untaxed accumulated and current earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, we determined, among other things, the amount of post-1986 E&P of the relevant subsidiaries. We recorded a provisional Transition Tax of $0.6 million which reduced our U.S. net deferred tax assets.
The Tax Act also reduced the U.S. corporate tax rate from 34% to 21%, effective January 1, 2018. Consequently, we have recorded a decrease to our tax effected U.S. net deferred tax assets of $31.6 million, with a corresponding decrease to the U.S. valuation allowance for the year ended December 31, 2017 as a result of re-measuring net deferred tax assets at the new lower corporate tax rate of 21%.
The Tax Act allows for the immediate write off of the cost of qualified property acquired and placed in service after September 27, 2017 and before January 1, 2023. Following January 1, 2023, the expensing phases down 20% annually through January 1, 2027. We recorded an immediate write off of $12.4 million for the year ending December 31, 2017.
At December 31, 2017, we had U.S. federal net operating loss carryforwards, or NOLs, of approximately $238.7 million, which will begin to expire in 2027. At December 31, 2017, we had state NOLs of approximately $139.8 million, which will also begin to expire in 2027. At December 31, 2017, the Company had foreign NOLs of approximately $23.8 million, which will begin to expire in 2026. At December 31, 2017, we had federal research and development tax credit carryforwards, or credit carryforwards, of approximately $10.2 million, which will begin to expire in 2027. At December 31, 2017, we had state research and development tax credits of approximately $8.0 million, which carry forward indefinitely. At December 31, 2017, the Company had foreign research tax credits of approximately $0.7 million, which carry forward indefinitely. Utilization of certain NOLs and credit carryforwards may be subject to an annual limitation due to ownership change limitations set forth in the Code and similar state provisions. Any future annual limitation may result in the expiration of NOLs and credit carryforwards before utilization. A prior ownership change and certain acquisitions resulted in us having NOLs subject to insignificant annual limitations.
Additionally, for tax years beginning after December 31, 2017, the Tax Act limits the NOL deduction to 80% of taxable income, repeals carryback of all NOLs arising in a tax year ending after 2017, and permits indefinite carryforward for all such NOLs. NOL’s arising in a tax year ending in or before 2017 can offset 100% of taxable income, are available for carryback, and expire 20 years after they arise.

Non-GAAP Financial Measures and Operational Performance Measures
In addition to our GAAP results, we review certain non-GAAP financial measures to help us evaluate our business, measure our performance, identify trends affecting our business, establish budgets, measure the effectiveness of investments in our technology and development and sales and marketing, and assess our operational efficiencies. These non-GAAP measures include advertising spend, non-GAAP net revenue, and Adjusted EBITDA, which are discussed immediately following the table below. Revenue and other GAAP measures are discussed under the headings "Components of Our Results of Operations" and "Results of Operations".
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Financial Measures and Non-GAAP Financial Measures:
 
 
 
 
 
 
Revenue
 
$
155,545

 
$
278,221

 
$
248,484

Advertising spend
 
$
837,221

 
$
1,025,782

 
$
1,004,751

Non-GAAP net revenue
 
$
154,928

 
$
256,098

 
$
227,321

Net income (loss)
 
$
(154,783
)
 
$
(18,053
)
 
$
422

Adjusted EBITDA
 
$
(4,420
)
 
$
70,920

 
$
59,466

Operational Measure:
 
 
 
 
 
 
Take Rate
 
18.5
%
 
25.0
%
 
22.6
%

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Advertising Spend
We define advertising spend as the buyer spending on advertising transacted on our platform. Advertising spend does not represent revenue reported on a GAAP basis. Tracking our advertising spend allows us to compare our results to the results of companies that report all spending transacted on their platforms as GAAP revenue on a gross basis. We also use advertising spend for internal management purposes to assess market share of total advertising spending.
Our advertising spend may be influenced by demand for our services, the volume and characteristics of paid impressions, average CPM, and other factors such as changes in the market, our execution of the business, and competition.
Advertising spend may fluctuate due to seasonality. We generally experience higher advertising spend during the fourth quarter of a given year because many buyers devote a disproportionate amount of their advertising budgets to this period of the year to coincide with increased holiday purchasing. Buyers’ focus on the fourth quarter generates more bidding activity on our platform, which may drive higher volumes of paid impressions or average CPM. Growth in our advertising spend slowed significantly in 2016 for various reasons, including shift of spending on digital advertising from desktop, which represents the majority of our business, to mobile, our delay in embracing header bidding, and absorption by competitors, principally Google and Facebook, of an increasing share of growth in spending on digital advertising. While we believe we have regained momentum in header bidding, these factors continued throughout 2017, causing a decline in advertising spend for the year.
The following table presents the reconciliation of revenue to advertising spend:
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Revenue
 
$
155,545

 
$
278,221

 
$
248,484

Plus amounts paid to sellers(1)
 
681,676

 
747,561

 
756,267

Advertising spend
 
$
837,221

 
$
1,025,782

 
$
1,004,751

(1)
Amounts paid to sellers for the portion of our revenue reported on a net basis for GAAP purposes.
Our solution enables buyers and sellers to transact through desktop and mobile channels. The following table presents revenue and advertising spend in dollar terms by channel and as a percentage of total revenue or advertising spend for the years ended December 31, 2017 and 2016. This information is not readily available for the year ended December 31, 2015.
 
 
Revenue
 
Advertising Spend
 
 
Year Ended
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2017
 
December 31, 2016
 
 
(in thousands, except percentages)
Channel:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Desktop
 
$
84,327

 
54
%
 
$
181,407

 
65
%
 
$
475,258

 
57
%
 
$
684,782

 
67
%
Mobile
 
71,218

 
46

 
96,814

 
35

 
361,963

 
43

 
341,000

 
33

Total
 
$
155,545

 
100
%
 
$
278,221

 
100
%
 
$
837,221

 
100
%
 
$
1,025,782

 
100
%
Non-GAAP Net Revenue
We define non-GAAP net revenue as GAAP revenue less amounts we pay sellers that are included within cost of revenue for the portion of our revenue reported on a gross basis. The portion of our revenue reported on a gross basis was attributable to intent marketing services, which no longer generated revenue after the first quarter of 2017. Historically, non-GAAP net revenue was a useful measure in assessing the performance of our business in periods for which our revenue included revenue reported on a gross basis, because it showed the operating results of our business on a consistent basis without the effect of differing revenue reporting (gross vs. net) that we applied under GAAP across different types of transactions, and facilitated comparison of our results to the results of companies that report all of their revenue on a net basis. Revenue from intent marketing services in the first quarter of 2017 created the difference between our non-GAAP net revenue and our GAAP revenue for the current year; however, we ceased offering that solution in that quarter. In future periods intent marketing no longer will be a reconciling item between GAAP and non-GAAP net revenue. Beginning in 2018, as all of our revenue will be reported on a net basis, non-GAAP net revenue will no longer be an additional measure used to assess our performance, as it will be the same as our GAAP revenue.

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A potential limitation of non-GAAP net revenue is that other companies may define non-GAAP net revenue differently, which may make comparisons difficult.
Non-GAAP net revenue is influenced by demand for our services, the volume and characteristics of advertising spend, and our take rate. The revenue we have reported on a gross basis was associated with our intent marketing business. Because we exited that business in the first quarter of 2017, we do not expect to report any revenue on a gross basis after the first quarter of 2017 unless and until we change our business practices, develop new products, or make an acquisition, in each case with characteristics that require gross reporting.
The following table presents a reconciliation of revenue to non-GAAP net revenue for the years ended December 31, 2017, 2016 and 2015.
 
 
Year Ended
 
 
December 31, 2017
 
December 31, 2016
 
December 31, 2015
 
 
(in thousands)
Revenue
 
$
155,545

 
$
278,221

 
$
248,484

Less amounts paid to sellers(1)
 
617

 
22,123

 
21,163

Non-GAAP net revenue
 
$
154,928

 
$
256,098

 
$
227,321

(1
)
Represents amounts paid to sellers included within cost of revenue.
Adjusted EBITDA
We define Adjusted EBITDA as net income (loss) adjusted to exclude stock-based compensation expense, depreciation and amortization, amortization of acquired intangible assets, impairment charges, interest income or expense, and other cash and non-cash based income or expenses that we do not consider indicative of our core operating performance, including, but not limited to foreign exchange gains and losses, acquisition and related items, and provision (benefit) for income taxes. We believe Adjusted EBITDA is useful to investors in evaluating our performance for the following reasons:
Adjusted EBITDA is widely used by investors and securities analysts to measure a company’s performance without regard to items such as those we exclude in calculating this measure, which can vary substantially from company to company depending upon their financing, capital structures, and the method by which assets were acquired.
Our management uses Adjusted EBITDA in conjunction with GAAP financial measures for planning purposes, including the preparation of our annual operating budget, as a measure of performance and the effectiveness of our business strategies, and in communications with our board of directors concerning our performance. Adjusted EBITDA may also be used as a metric for determining payment of cash incentive compensation.
Adjusted EBITDA provides a measure of consistency and comparability with our past performance that many investors find useful, facilitates period-to-period comparisons of operations, and also facilitates comparisons with other peer companies, many of which use similar non-GAAP financial measures to supplement their GAAP results.    
Although Adjusted EBITDA is frequently used by investors and securities analysts in their evaluations of companies, Adjusted EBITDA has limitations as an analytical tool, and should not be considered in isolation or as a substitute for analysis of our results of operations as reported under GAAP. These limitations include:
Stock-based compensation is a non-cash charge and is and will remain an element of our long-term incentive compensation package, although we exclude it as an expense when evaluating our ongoing operating performance for a particular period.
Depreciation and amortization are non-cash charges, and the assets being depreciated or amortized will often have to be replaced in the future, but Adjusted EBITDA does not reflect any cash requirements for these replacements.
Impairment charges are non-cash charges related to goodwill, intangible assets and/or long-lived assets.
Adjusted EBITDA does not reflect non-cash charges related to acquisition and related items, such as amortization of acquired intangible assets and changes in the fair value of contingent consideration.
Adjusted EBITDA does not reflect cash and non-cash charges and changes in, or cash requirements for, acquisition and related items, such as certain transaction expenses and expenses associated with earn-out amounts.
Adjusted EBITDA does not reflect changes in our working capital needs, capital expenditures, or contractual commitments.
Adjusted EBITDA does not reflect cash requirements for income taxes and the cash impact of other income or expense.
Other companies may calculate Adjusted EBITDA differently than we do, limiting its usefulness as a comparative measure.

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Our Adjusted EBITDA is influenced by fluctuation in our revenue and the timing and amounts of our investments in our operations.
Adjusted EBITDA should not be considered as an alternative to net income (loss), operating loss, or any other measure of financial performance calculated and presented in accordance with GAAP. The following table presents a reconciliation of net income (loss), the most comparable GAAP measure, to Adjusted EBITDA for the years ended December 31, 2017, 2016 and 2015: