On the regulation of personal data distribution in online advertising platforms

Online tracking is the key enabling technology of modern online advertising. In the recently established model of real-time bidding (RTB), the web pages tracked by ad platforms are shared with advertising agencies (also called DSPs), which, in an auction-based system, may bid for user ad impressions. Since tracking data are no longer confined to ad platforms, RTB poses serious risks to privacy, especially with regard to user profiling, a practice that can be conducted at a very low cost by any DSP or related agency, as we reveal here. In this work, we illustrate these privacy risks by examining a data set with the real ad-auctions of a DSP, and show that for at least 55% of the users tracked by this agency, it paid nothing for their browsing data. To mitigate this abuse, we propose a system that regulates the distribution of bid requests (containing user tracking data) to potentially interested bidders, depending on their previous behavior. In our approach, an ad platform restricts the sharing of tracking data by limiting the number of DSPs participating in each auction, thereby leaving unchanged the current RTB architecture and protocols. However, doing so may have an evident impact on the ad platform’s revenue. The proposed system is designed accordingly, to ensure the revenue is maximized while the abuse by DSPs is prevented to a large degree. Experimental results seem to suggest that our system is able to correct misbehaving DSPs, and consequently enhance user privacy.Peer ReviewedPostprint (author's final draft

Privacy in online advertising platforms

Online advertising is consistently considered as the pillar of the "free• content on the Web since it is commonly the funding source of websites. Furthermore, the option of delivering personalizad ads has tumed advertising into a really valuable service for users, who receive ads tailored to their interests. Given its success in getting paying customers, online advertising is fueling a billionaire business. The current advertising model builds upon an intricate infrastructure whose main aim is to deliver personalized ads. For this purpose, a wealth of user data is collected, aggregated, processed and traded at an unprecedented rate. However, the intrusiveness and ubiquity of these practices prorrpt serious privacy concems. In view of the inherent corrplexity behind the operation of ad platforms, privacy risks in the online advertising ecosystem could be studied from multiple perspectives. Naturally, most of the efforts unveiling these privacy issues concentrate on a specific entity, technology, behavior or context. However, such a segmented approach rright underestimate the benefits of a wider vision of a systerric problem. A lot of privacy protection echanisms have been proposed from the industry and acaderria. The most popular ones resort to radical strategies that hinder the ad distribution process, thus seriously affecting the online advertising ecosystem. Others involve significantly changing the ecosystem, which unfortunately may not be suitable in these times. Consequently, to encourage the adoption of privacy protection in this context, it is fundamental to pose mechanisms that aim at balancing the trade-off between user privacy and the web business model. First, this thesis deals with the need to have a wide perspective of the privacy risks for users within the online advertising ecosystem and the protection approaches available. We survey the online advertising infrastructure and its supporting technologies, and present a thorough overview of the undertying privacy risks and the solutions that may rritigate them. Through a systematic effort, we analyze the threats and potential privacy attackers in this scenario of online advertising.Then, we conduct a corrprehensive survey of the most relevant privacy mechanisms, and classify and con-pare them on the basis of their privacy guarantees and irrpact on the Web. Subsequently, we study the privacy risks derived from real-time bidding, a key enabling technology of modem online advertising. We experimentally explore the potential abuse of the process of user data sharing, necessary to support the auction-based system in online advertising. Accordingly, we propase a system to regula te the distribution of u ser tracking data to potentially interested entities, depending on their previous behavior.This consists in reducing the nurnber of advertising agencies receiving user data. Doing so may affect the ad platform's revenue, thus the proposed system is designed to maxirrize the revenue while the abuse by advertising agencies is prevented to a large degree. Experimentally, the results of evaluation suggest that this system is able to correct rrisbehaving entities, consequently enhancing user privacy. Finally, we analyze the irrpact of online advertising and tracking from the particular perspective of lberoamerica.We study the third-party and ad tracking triggered within local websites in this heterogeneous region not previously studied. We found out that user location in this context would affect privacy since the intensity of third-party traffic, including advertising related flows of information, varies from country to country when local web traffic is simulated, although the total nurnber of entities behind this traffic seems stable. The type of content served by websites is also a parameter affecting the leve! of third-party tracking:publishers assiciated with news shopping categories generate more third-party traffic and such intensity is exarbated for top-world sitesLa publicitat en línia té un paper important a Internet que permet finançar habitualment l'operació de llocs web que ofereixen contingut lliure als usuaris. A més, la personalització dels anuncis ha tornat la publicitat en línia un servei valuós per als usuaris. Si aconseguirem que hi hagi molts compradors siguin més que possibles, es promourà un negoci milionari. El model d'anuncis vigents es basa en una infraestructura completa que lliura els anuncis personalitzats. Pera això, es pot recopilar una gran quantitat de dades d'ús, agregar, processar i vendre molt ràpidament. Malauradament, aquestes pràctiques generen riscos de privadesa. Donada la complexitat de l'operació de les plataformes d'anuncis, els riscos de privacitat es poden estudiar des de diverses perspectives. Naturalment, els esforços per desenvolupar aquests problemes de privacitat es concentren en una entitat, tecnologia, comportament o context específic. Però aquest enfocament subestima els beneficis d'una perspectiva més àmplia d'un problema integral. Molts mecanismes de protecció han estat proposats des de la indústria i l’àmbit acadèmic. Els més populars apliquen estratègies radicals que obstrueixen la distribució d'anuncis, afectant seriosament l’ecosistema d'anuncis. També es pot modificar significativament l’ecosistema, el que no és factible per la seva conflictivitat. Així, amb la finalitat de fomentar l'adopció de protecció de privacitat, és fonamental plantejar solucions orientades a equilibrar les necessitats de privacitat amb el model de negocis de la web. Inicialment, la tesi ofereix una visió amplia dels riscos de privacitat i els mecanismes de protecció a ecosistema d'anuncis en línia. Això es pot aconseguir basant-se en una revisió de la infraestructura i tecnologies subjacents en aquest context. Analitza sistemàticament les amenaces i potencies atacants. A continuació es revisa exhaustivament els mecanismes de privacitat més rellevants, i es classifica i es compara segons les garanties de privacitat que s'ofereixen i el seu possible impacte a la web. Seguidament, s'estudia els riscos de privadesa derivats de les ofertes en temps real, una tecnologia clau del sistema d'anuncis en línia modern. Experimentalment, s'inverteixen els riscos del procés de distribució de dades d'ús, part del sistema basat en licitacions de la publicitat en línia. Es proposa un sistema que regula la distribució de dades d'ús a tercers, depenent del seu comportament previ. Això consisteix en reduir el nombre d’agències anunciants que rebin dades d'ús. Per mitigar l’impacte sobre els ingressos del sistema d'anuncis, aquesta reducció és malaltia i l'objectiu de maximitzar els declaracions ingressades. Experimentalment, es troba que el sistema proposat corregir els comportaments maliciosos, millorant la privacitat dels usuaris. Finalment, s'analitza l'impacte del rastre i la publicitat en línia des de la perspectiva iberoamericana. Estudiem el rastreig de tercers i allò relacionat amb els anuncis que se generen en llocs web locals en aquesta regió heterogènia. Trobem que la ubicació de l'usuari en aquest context afecta la privacitat de l'usuari ja que aquest rastreig varia de país a país, tot i que el nombre total d'entitats darrere d'aquest transit sembla estable. El tipus de contingut afecta també el nivell de rastreig: llocs web de noticies o de compres generen més transit cap a tercers i aquesta intensitat s'exacerba en els llocs més populars

Privacy in online advertising platforms

Online advertising is consistently considered as the pillar of the "free• content on the Web since it is commonly the funding source of websites. Furthermore, the option of delivering personalizad ads has tumed advertising into a really valuable service for users, who receive ads tailored to their interests. Given its success in getting paying customers, online advertising is fueling a billionaire business. The current advertising model builds upon an intricate infrastructure whose main aim is to deliver personalized ads. For this purpose, a wealth of user data is collected, aggregated, processed and traded at an unprecedented rate. However, the intrusiveness and ubiquity of these practices prorrpt serious privacy concems. In view of the inherent corrplexity behind the operation of ad platforms, privacy risks in the online advertising ecosystem could be studied from multiple perspectives. Naturally, most of the efforts unveiling these privacy issues concentrate on a specific entity, technology, behavior or context. However, such a segmented approach rright underestimate the benefits of a wider vision of a systerric problem. A lot of privacy protection echanisms have been proposed from the industry and acaderria. The most popular ones resort to radical strategies that hinder the ad distribution process, thus seriously affecting the online advertising ecosystem. Others involve significantly changing the ecosystem, which unfortunately may not be suitable in these times. Consequently, to encourage the adoption of privacy protection in this context, it is fundamental to pose mechanisms that aim at balancing the trade-off between user privacy and the web business model. First, this thesis deals with the need to have a wide perspective of the privacy risks for users within the online advertising ecosystem and the protection approaches available. We survey the online advertising infrastructure and its supporting technologies, and present a thorough overview of the undertying privacy risks and the solutions that may rritigate them. Through a systematic effort, we analyze the threats and potential privacy attackers in this scenario of online advertising.Then, we conduct a corrprehensive survey of the most relevant privacy mechanisms, and classify and con-pare them on the basis of their privacy guarantees and irrpact on the Web. Subsequently, we study the privacy risks derived from real-time bidding, a key enabling technology of modem online advertising. We experimentally explore the potential abuse of the process of user data sharing, necessary to support the auction-based system in online advertising. Accordingly, we propase a system to regula te the distribution of u ser tracking data to potentially interested entities, depending on their previous behavior.This consists in reducing the nurnber of advertising agencies receiving user data. Doing so may affect the ad platform's revenue, thus the proposed system is designed to maxirrize the revenue while the abuse by advertising agencies is prevented to a large degree. Experimentally, the results of evaluation suggest that this system is able to correct rrisbehaving entities, consequently enhancing user privacy. Finally, we analyze the irrpact of online advertising and tracking from the particular perspective of lberoamerica.We study the third-party and ad tracking triggered within local websites in this heterogeneous region not previously studied. We found out that user location in this context would affect privacy since the intensity of third-party traffic, including advertising related flows of information, varies from country to country when local web traffic is simulated, although the total nurnber of entities behind this traffic seems stable. The type of content served by websites is also a parameter affecting the leve! of third-party tracking:publishers assiciated with news shopping categories generate more third-party traffic and such intensity is exarbated for top-world sitesLa publicitat en línia té un paper important a Internet que permet finançar habitualment l'operació de llocs web que ofereixen contingut lliure als usuaris. A més, la personalització dels anuncis ha tornat la publicitat en línia un servei valuós per als usuaris. Si aconseguirem que hi hagi molts compradors siguin més que possibles, es promourà un negoci milionari. El model d'anuncis vigents es basa en una infraestructura completa que lliura els anuncis personalitzats. Pera això, es pot recopilar una gran quantitat de dades d'ús, agregar, processar i vendre molt ràpidament. Malauradament, aquestes pràctiques generen riscos de privadesa. Donada la complexitat de l'operació de les plataformes d'anuncis, els riscos de privacitat es poden estudiar des de diverses perspectives. Naturalment, els esforços per desenvolupar aquests problemes de privacitat es concentren en una entitat, tecnologia, comportament o context específic. Però aquest enfocament subestima els beneficis d'una perspectiva més àmplia d'un problema integral. Molts mecanismes de protecció han estat proposats des de la indústria i l’àmbit acadèmic. Els més populars apliquen estratègies radicals que obstrueixen la distribució d'anuncis, afectant seriosament l’ecosistema d'anuncis. També es pot modificar significativament l’ecosistema, el que no és factible per la seva conflictivitat. Així, amb la finalitat de fomentar l'adopció de protecció de privacitat, és fonamental plantejar solucions orientades a equilibrar les necessitats de privacitat amb el model de negocis de la web. Inicialment, la tesi ofereix una visió amplia dels riscos de privacitat i els mecanismes de protecció a ecosistema d'anuncis en línia. Això es pot aconseguir basant-se en una revisió de la infraestructura i tecnologies subjacents en aquest context. Analitza sistemàticament les amenaces i potencies atacants. A continuació es revisa exhaustivament els mecanismes de privacitat més rellevants, i es classifica i es compara segons les garanties de privacitat que s'ofereixen i el seu possible impacte a la web. Seguidament, s'estudia els riscos de privadesa derivats de les ofertes en temps real, una tecnologia clau del sistema d'anuncis en línia modern. Experimentalment, s'inverteixen els riscos del procés de distribució de dades d'ús, part del sistema basat en licitacions de la publicitat en línia. Es proposa un sistema que regula la distribució de dades d'ús a tercers, depenent del seu comportament previ. Això consisteix en reduir el nombre d’agències anunciants que rebin dades d'ús. Per mitigar l’impacte sobre els ingressos del sistema d'anuncis, aquesta reducció és malaltia i l'objectiu de maximitzar els declaracions ingressades. Experimentalment, es troba que el sistema proposat corregir els comportaments maliciosos, millorant la privacitat dels usuaris. Finalment, s'analitza l'impacte del rastre i la publicitat en línia des de la perspectiva iberoamericana. Estudiem el rastreig de tercers i allò relacionat amb els anuncis que se generen en llocs web locals en aquesta regió heterogènia. Trobem que la ubicació de l'usuari en aquest context afecta la privacitat de l'usuari ja que aquest rastreig varia de país a país, tot i que el nombre total d'entitats darrere d'aquest transit sembla estable. El tipus de contingut afecta també el nivell de rastreig: llocs web de noticies o de compres generen més transit cap a tercers i aquesta intensitat s'exacerba en els llocs més populars.Postprint (published version

Inefficiencies in Digital Advertising Markets

Digital advertising markets are growing and attracting increased scrutiny. This article explores four market inefficiencies that remain poorly understood: ad effect measurement, frictions between and within advertising channel members, ad blocking, and ad fraud. Although these topics are not unique to digital advertising, each manifests in unique ways in markets for digital ads. The authors identify relevant findings in the academic literature, recent developments in practice, and promising topics for future research

Environmental analysis for application layer networks

Die zunehmende Vernetzung von Rechnern über das Internet lies die Vision von Application Layer Netzwerken aufkommen. Sie umfassen Overlay Netzwerke wie beispielsweise Peer-to-Peer Netzwerke und Grid Infrastrukturen unter Verwendung des TCP/IP Protokolls. Ihre gemeinsame Eigenschaft ist die redundante, verteilte Bereitstellung und der Zugang zu Daten-, Rechen- und Anwendungsdiensten, während sie die Heterogenität der Infrastruktur vor dem Nutzer verbergen. In dieser Arbeit werden die Anforderungen, die diese Netzwerke an ökonomische Allokationsmechanismen stellen, untersucht. Die Analyse erfolgt anhand eines Marktanalyseprozesses für einen zentralen Auktionsmechanismus und einen katallaktischen Markt. --Grid Computing

Suljettujen online-mainosalustojen strategiat — tapaukset Google ja Facebook

This thesis studies closed ad platforms in the modern online advertising industry. The research in the field is still nascent and the concept of a closed ad platform doesn’t exist. The objective of the research was to discover the main factors determining the revenue of online advertising platforms and to understand why some publishers choose to establish their own closed ad platforms instead of selling their inventory for third-party ad platforms. The concept of a closed ad platform is defined leveraging the existing online advertising literature and the platform governance structure theory. Using the case study method, Google and Facebook were chosen as the cases as they have driven most of the innovation in the field and quickly gained significant market share. In total, 47 people were interviewed for this study, most of them working for advanced online advertisers. Based on the interviews, a microeconomic mathematic formula is created for modeling an ad platform’s net advertising revenue. The formula is used to identify the five main drivers of an ad platform’s revenue an each of them are studied in depth. The results suggest that the most important revenue drivers the ad platforms can affect are access to an active user base, the efficiency of ad serving and the comprehensiveness of measurement. Setting up a closed ad platform requires significant investments from a publisher and should be only done if it can improve the advertisers’ results. After it’s been established, a closed platform can leverage its position to collect user data and structured business data to optimize its performance further. The results provide a structured understanding of the main dynamics in the industry that can be used in decision-making and a basis for future research on closed ad platforms.Tämä diplomityö tutkii suljettuja mainosalustoja nykyaikaisella online-mainonta-alalla. Alan tutkimus on vielä aluillaan ja suljetun mainosalustan konseptia ei ole olemassa. Tämän tutkimuksen tavoitteena oli löytää online-mainosalustojen liikevaihdon määrittävät tekijät ja ymmärtää miksi jotkut julkaisijat valitsevat omien suljettujen mainosalustojen perustamisen mainospaikkojen kolmansien osapuolien mainosalustoille myymisen sijaan. Suljetun mainosalustan konsepti määritellään olemassaolevaa online- mainontakirjallisuutta ja alustojen hallintarakenneteoriaa hyödyntäen. Tapaustutkimusmenetelmää käyttäen, Google ja Facebook valittiin tapauksiksi, sillä ne ovat ajaneet eniten innovaatioita alalla ja nopeasti saavuttaneet merkittävän markkinaosuuden. Yhteensä 47 henkilöä haastateltiin tätä tutkimusta varten, useimmat heistä edistyneiden online-mainostajien työntekijöitä. Haastattelujen perusteella luodaan mikrotaloudellinen matemaattinen kaava mainosalustan nettoliikevaihdon mallintamiseksi. Kaavaa käytetään tunnistamaan mainosalustan liikevaihdon viisi pääkomponenttia, ja kuhunkin niistä perehdytään syvällisemmin. Tulokset viittaavat, että tärkeimmät liikevaihdon ajurit, joihin mainosalustat voivat vaikuttaa ovat pääsy aktiiviseen käyttäjäkantaan, mainosten näyttämisen tehokkuus ja mittaamisen kattavuus. Suljetun mainosalustan perustaminen vaatii merkittäviä investointeja julkaisijalta ja tulisi tehdä ainoastaan, jos sillä voidaan parantaa mainostajien tuloksia. Suljetun alustan perustamisen jälkeen sen positiota voidaan hyödyntää käyttäjädatan ja strukturoidun liiketoimintadatan keräämiseksi suorituskyvyn edelleen optimoimiseksi. Tulokset tarjoavat toimialan päädynamiikkojen ymmärryksen, jota voidaan käyttää päätöksenteossa sekä pohjana suljettujen mainosalustojen edelleen tutkimiseksi tulevaisuudessa

Competition between demand-side intermediaries in ad exchanges

Online advertising constitutes one of the main sources of revenue for the majority of businesses on the web. Online advertising inventory was traditionally traded via bilateral contracts between publishers and advertisers, vastly through a number of intermediaries. However, what caused an explosion in the volume and, consequently, the revenue of online ads was the incorporation of auctions as the major mechanism for trading sponsored search ads in all major search engines. This reduced transaction costs and allowed for the advertisement of small websites which constitute the majority of Internet traffic. Auction-based markets were harder to establish in the display advertising industry due to the higher volume of inventory and the pre-existence of traditional intermediaries, often leading to inefficiencies and lack of transparency. Nevertheless, this has recently changed with the introduction of the ad exchanges, centralized marketplaces for the allocation of display advertising inventory that support auctions and real-time bidding. The appearance of ad exchanges has also altered the market structure of both demand-side and supply side intermediaries which increasingly adopt auctions to perform their business operations. Hence, each time a user enters a publisher's website, the contracted ad exchange runs an auction among a number of demand-side intermediaries, each of which represents their interested advertisers and typically submits a bid by running a local auction among these advertisers.Against this background, within this thesis, we look both at the auction design problem of the ad exchange and the demand-side intermediaries as well as at the strategies to be adopted by advertisers. Specifically, we study the revenue and efficiency effects of the introduction and competition of the demand-side intermediaries in a single-item auction setting with independent private valuations. The introduction of these intermediaries constitutes a major issue for ad exchanges since they hide some of the demand from the ad exchange and hence can make a profit by pocketing the difference between what they receive from their advertisers and what they pay at the exchange. Ad exchanges were created to offer transparency to both sides of the market, so it is important to study the share of the revenue that intermediaries receive to justify their services offered given the competition they face by other such intermediaries. The existence of mediators is a well-known problem in other settings. For this reason, our formulation is general enough to encompass other areas where two levels of auctions arise, such as procurement auctions with subcontracting and auctions with colluding bidders.In more detail, we study the effects of the demand-side intermediaries' choice of auction for three widely used mechanisms, two variations of the second-price sealed-bid (known as Vickrey) auction, termed PRE and POST, and first-price sealed-bid (FPSB) auctions. We first look at a scenario with a finite number of intermediaries, each implementing the same mechanism, where we compare the profits attained for all stakeholders. We find that there cannot be a complete profit ranking of the three auctions: FPSB auctions yield higher expected profit for a small number of competing intermediaries, otherwise PRE auctions are better for the intermediaries. We also find that the ad exchange benefits from intermediaries implementing POST auctions. We then let demand-side intermediaries set reserve (or floor) prices, that are known to increase an auctioneer's expected revenue. For issues of analytical tractability, we only consider scenarios with two intermediaries but we also compare the two Vickrey variations in heterogeneous settings where one intermediary implements the first whereas the other implements the second variation. We find that intermediaries, in general, follow mixed reserve-price-setting strategies whose distributions are difficult to derive analytically. For this reason, we use the fictitious play algorithm to calculate approximate equilibria and numerically compare the revenue and efficiency of the three mechanisms for specific instances. We find that PRE seems to perform best in terms of attained profit but is less efficient than POST. Hence, the latter might be a better option for intermediaries in the long term.Finally, we extend the previous setting by letting advertisers strategically select one of the two intermediaries when the latter implement each of the two Vickrey variations. We analytically derive the advertisers' intermediary selection strategies in equilibrium. Given that, in some cases, these strategies are rather complex, we use again the fictitious play algorithm to numerically calculate the intermediaries' and the ad exchange's best responses for the same instances as before. We find that, when both intermediaries implement POST auctions, advertisers always select the low-reserve intermediary, otherwise they generally follow randomized strategies. Last, we find that the ad exchange benefits from intermediaries implementing the pre-award Vickrey variation compared to a setting with two heterogeneous Vickrey intermediary auctioneers, whereas the opposite is true for the intermediaries.<br/