The Rumpus claims to have an unauthorized interview with an anonymous Facebook employee. And according to that anonymous Facebook employee, Facebook "is recording data on everything you do on the site. Everything. And not just the messages you've written and received either: it knows how many times you've clicked on your friend's profile, which photos you've viewed, and more."
TechCrunch has a nice summary of the 3,000-word Rumpus piece. It alos says that Facebook employees once had a master password which would all allow them access to to any users profile and personal data.
It will be interesting to see how much attention this get and whether any of it is ever verified.