This [user][1] asked an off-topic [Facebook question][2] that I'm sure will be deleted soon about Facebook privacy if she were to work for the government in the future.  The user believes (wrongly) that her photos and wall posts are private. This is admittedly an issue between her and Facebook.  However, Stack Overflow is exposing her Facebook user id to the public.  People can take this, call http://graph.facebook.com/556966628, and then get a link to her profile, wall and photos that are completely wide open.  It seems like Stack Overflow could and should do more to protect the Facebook user id instead of broadcasting it. 

In fact, the [Facebook Platform Policies][3], mention that user id's should be kept confidential. Specifically: 
 

> II 6. You will not directly or indirectly transfer any data you receive from
> us, including user data or Facebook User IDs, to (or use such data in
> connection with) any ad network, ad exchange, data broker, or other
> advertising or monetization related toolset, even if a user consents
> to such transfer or use.

(Stack Exchange is an ad platform. This is what I would call a gray area.)

Also: 

> II 7. You will not use Facebook User IDs for any purpose outside your
> application (e.g., your infrastructure, code, or services necessary to
> build and run your application). Facebook User IDs may be used with
> external services that you use to build and run your application, such
> as a web infrastructure service or a distributed computing platform,
> but only if those services are necessary to running your application
> and the service has a contractual obligation with you to keep Facebook
> User IDs confidential.

Somewhat more private solutions would be:

 - Download the Facebook image and re-upload it to imgur.com and then run a process every so often to keep them in sync if they change (although this may be against Facebook TOS)
 - Follow the 302 redirect that the graph api url gives and store that more private image url to display the image (and then run a process every so often to keep it in sync). This is compliant with the Facebook TOS. 


  [1]: http://facebook.stackoverflow.com/users/966079/courtney-campbell
  [2]: http://stackoverflow.com/questions/7563230/history-of-posts-accessibility-to-future-employers
  [3]: https://developers.facebook.com/policy/