Looking beyond the Privacy Mirror

Over the last two weeks, I have been using my homegrown Facebook application, Privacy Mirror, as a means of experimenting with Facebook’s privacy settings. Although Facebook provides a nice interface to view your profile through your friends’ eyes, it does not do the same for applications. I built Privacy Mirror with the hopes of learning what 3rd party application developers can see of my profile by way of my friends’ use of applications. I have yet to speak with representatives of Facebook to confirm my findings, but I am confident in the following findings.

Imagine that Alice and Bob are friends in Facebook. Alice decides to add a new application, called App X, to her profile in Facebook. (For clarity’s sake, by “add”, I mean that she authorizes the application to see her profile. Examples of Facebook applications include Polls, Friend Wheel, Movies, etc.) At this point, App X can see information in Alice’s profile. App X can also see that Alice is friends with Bob; in fact, App X can see information in Bob’s profile. Bob can limit how much information about him is available to applications that his friends add to their profiles through the Application Privacy settings. In this case, let’s imaging that Bob has only allowed 3rd party applications to see his profile picture and profile status.

After a while, Alice tells Bob about App X. He thinks it sounds cool and adds it to his profile. At this point if App X, via Alice’s profile, looks at Bob’s profile it will see not only his profile picture and status but also his education history, hometown info, activities and movies. That is significantly more than what he authorized in his Application privacy settings. What is going here?

It appears what’s going on is that if Alice and Bob both have authorized the same application, that application no longer respects either user’s Application Privacy settings. Instead, it respects the Profile Privacy settings of each person. In essence, App X acts (from a privacy settings point of view) as if it were a friend of Alice and Bob and not a third-party application.

Putting my privacy commissioner hat for a moment, I’d want to analyze this situation from a consent and disclosure perspective. When Bob confirms his friendship with Alice he is, in a sense, opting in to a relationship with her. This opt-in indicates that he is willing to disclose certain information to Alice. Bob can control what information is disclosed to Alice through his Profile Privacy settings and this allows him to mitigate privacy concerns he has in terms of his relationship with Alice.

What Bob isn’t consenting to (and is not opting in to) is a relationship with Alice’s applications. Bob is completely unaware of which applications Alice currently has or will have in the future. This is an asymmetry of relationship. It is entirely possible that Alice and Bob will have applications in common and once they do the amount of profile information disclosed (by both of them) to an application can radically change and change without notice to either Alice or Bob. Furthermore, it is unclear which Facebook privacy settings Bob needs to manipulate to control what Alice’s applications can learn about him.

This lack of clarity is harmful. It shouldn’t take a few hundred lines of PHP, three debuggers, and an engineering degree to figure out how privacy controls work. This lack of clarity robs Facebook users of the opportunity to make meaningful and informed choices about their privacy.

This experiment started after I read the Canadian Privacy Commissioner’s report of findings on privacy complaints brought against Facebook. This report raised significant concerns about third-party applications and their access to profile information.

As of the beginning of Catalyst (today!), Facebook has about 15 days remaining to respond to the Canadian Privacy Commissioner’s office, I hope that this issue about third party applications and privacy controls is meaningfully addressed in Facebook’s response.

(Cross-posted with Burton Group’s Identity Blog.)