Thèse "Auditing, measuring, and bringing transparency to targeted advertising ecosystems" par Athanasios ANDREOU, lors de la journée Futur & Ruptures du 31 janvier 2019. Une journée scientifique pour présenter l’ensemble des travaux de thèses aboutis portant sur des thématiques prospectives du programme de l’IMT.

1. AUDITING, MEASURING, AND BRINGING
TRANSPARENCY TO TARGETED
ADVERTISING ECOSYSTEMS
ATHANASIOS ANDREOU

2. NEED FOR TRANSPARENCY IN TARGETED ADVERTISING
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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o Targeted advertising is prevalent:
• Facebook's ad revenue in 2016: 27B$ (Source: statista.com)
oVery frequently black boxes
oUse users' personal data at a massive scale
oHave social and political impact:
We focus on transparency in targeted advertising
oTransparency on how these systems work is important
oReflected in legislation (GDPR)

3. 1. TARGETED ADVERTISING IN FACEBOOK
2. AUDITING FACEBOOK TRANSPARENCY MECHANISMS (NDSS2018)
3. MEASURING THE FACEBOOK ADVERTISING ECOSYSTEM (NDSS2019)
4. BRINGING COLLABORATIVE TRANSPARENCY TO TARGETED ADVERTISING
5. ADANALYST- A TOOL TO HELP USERS MAKE SENSE OF THEIR ADS
THIS TALK

4. TARGETED ADVERTISING IN FACEBOOK

5. TARGETED ADVERTISING IN FACEBOOK
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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Why am I seeing this ad?

6. HOW ADVERTISERS TARGET USERS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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7. MANY ATTRIBUTES AVAILABLE FOR TARGETING
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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8. EVEN MORE TARGETING TYPES
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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9. FACEBOOK HAS EXPLANATIONS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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10. FACEBOOK HAS EXPLANATIONS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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11. AUDITING FACEBOOK TRANSPARENCY MECHANISMS
(NDSS2018)

12. DESIRED PROPERTIES OF EXPLANATIONS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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oDo explanations show all the attributes?
• Completeness
oAre they correct?
• Correctness
oAre they personalized?
• Personalization
oDo similar ads show similar explanations?
• Determinism
oAre explanations for users consistent?
• Consistency

13. EXPERIMENTS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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oBrowser extension to collect ads from Facebook timeline
• 35 users for 5 months
• 26K unique ads and explanations
oControlled experiments targeting users with ads
• We targeted users
• We collected explanations
• 96 successful experiments
Ground truth

14. EXAMPLE OF EXPLANATIONS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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15. EVALUATION
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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o Are explanantions complete?:
• 61 Controlled experiments (e.g. target users interested in Instant messaging AND
Mobile Phones)
• Only one attribute appears in the explanation (e.g. Instant messaging)
oWhich attribute appears?
• Depends on attribute type (e.g. Demographics>Interests>Behaviors)
• Depends on audience size (least unique attribute appears)
oExplanations are incomplete
o Incomplete explanations:
• malicious advertiser can conceal sensitive/discriminatory attributes
• by adding a common popular attribute to the targeting audience
Establishing properties can help create better explanations

16. MEASURING THE FACEBOOK ADVERTISING ECOSYSTEM
(NDSS2019)

17. AIMS AND DATASETS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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oQuestions:
• Who are the advertisers?
• How are they targeting users?
o Dataset:
• More than 600 users, 200K ads, 40K advertisers
• Across the globe

18. RESULTS
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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oWho are the advertisers?
• ~10% from sensitive categories such as News and Politics, Finance, Medical Health...
• 38.9% of ads come from unverified advertisers
o How are they targeting users?
• 21% of ads use Data Brokers, PII-based and Lookalike Audiences
• North America vs Europe (e.g. for PII-based 6 vs 2%)
• Advertisers from News and Politics tailor their ads over time, users and attributes
Need for extra transparency!

19. BRINGING COLLABORATIVE TRANSPARENCY TO TARGETED
ADVERTISING

20. IDEA: COLLABORATIVE TRANSPARENCY
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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o Group users that received the same ad together
o Infer targeting from group properties of users that received the same ad:
• which attributes do users that received the same ad share?
• how can we use them?

21. ADANALYST- A TOOL TO HELP USERS MAKE SENSE OF THEIR
ADS

22. ADANALYST
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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ohttps://adanalyst.mpi-sws.org
o Enhance transparency by aggregated statistics
o Who else received this ad?
Disable adblockers and anti-tracking!
Set Facebook in French or English!

23. CONCLUSION
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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o We audited Facebook transparency mechanisms and identified weaknesses
o We show how are advertisers targeting users and found concerning practices
o We bring more transparency to users in a collaborative way
o We provide users with a tool that helps them make sense of their ads

24. THE END
AUDITING, MEASURING, AND BRINGING TRANSPARENCY TO TARGETED ADVERTISING ECOSYSTEMS
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Questions?