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.

Further findings from the Privacy Mirror experiment

I find that I rely on my debugging skills in almost every aspect of my life: cooking, writing, martial arts, photography… And it helps when you’ve got friends who a good debuggers as well. In this case, my friends lent a hand helping me figure out what I was seeing in my Privacy Mirror.

The following is a snapshot of the Application Privacy settings I have set in Facebook:

Facebook Application Privacy Settings

Given these settings, I would expect that the Facebook APIs would report the following to a 3rd party application developer:

  • My name
  • My networks
  • My friends ids
  • My profile status