C MU U sable P rivacy and S ecurity Laboratory 1 Privacy Policy, Law and Technology Search Engines and Social Networks October 21, 2008

Online Social Networks

C MU U sable P rivacy and S ecurity Laboratory 3 graph from compete.com

C MU U sable P rivacy and S ecurity Laboratory 4 MySpace  Profiles available to the public –No login required to view information  Used for “Social Browsing” –Finding new friends

C MU U sable P rivacy and S ecurity Laboratory 5 Privacy Settings

C MU U sable P rivacy and S ecurity Laboratory 6 Facebook  Perceived as a “closed community” or “for college students only” –Login required to access profiles  User for “Social Searching” –Finding existing friends, or people met in person

C MU U sable P rivacy and S ecurity Laboratory 7 Privacy Scandals  Facebook Mini-Feed/Feed Uproar –Introduced in Fall 2006 –Aggregates all “Friend” profile updates –Aggregates all actions taken on Facebook –Generated Uproar and User Backlash  User base opened to everyone –Added geographical networks –No longer limits to.edu addresses

C MU U sable P rivacy and S ecurity Laboratory 8 Pimp My Privacy  New Privacy Features introduced –Enhanced Settings –Specific Mini-Feed information can be removed –Access control granularity increased to the Network Level –Limited Profile introduced

C MU U sable P rivacy and S ecurity Laboratory 9

C MU U sable P rivacy and S ecurity Laboratory 10

C MU U sable P rivacy and S ecurity Laboratory 11

C MU U sable P rivacy and S ecurity Laboratory 12

C MU U sable P rivacy and S ecurity Laboratory 13 Privacy In Facebook  People are more privacy-protective than default setting

C MU U sable P rivacy and S ecurity Laboratory 15 Search engines  Search engine query logs can be very revealing  Provide insights into what people are doing, interested in, thinking about  Can be connected to form longitudinal profile  Difficult to anonymize completely  2006 AOL search log release – – –DEMO

16 Why share query logs? Academia has difficulty contributing to web search Untold insights into human behavior exist within logs Source: Andrew Tomkins

17 Why not share query logs? Source: Andrew Tomkins

18 “Person” attack versus “Trace” attack Trace attack: given a trace, identify the person Person attack: the dual Adversaries in person attack: –“Neighborly” knowledge –Query knowledge –Browser compromise Source: Andrew Tomkins

19 Person attack (750K users) Source: Andrew Tomkins

C MU U sable P rivacy and S ecurity Laboratory 20 Discussion  What are the privacy risks associated with social networks and search engines?  What are the web sites doing to mitigate these risks?  Is it enough?  Is opting in to having your data collected and/or shared sufficient?