"My friend got a call from her friend at Facebook, asking why she kept looking at his profile," says a privacy-conscious source at a major tech company. Turns out Facebook employees can (and do) check out anyone's profile. Not only that, but they also see which profiles a user has viewed — a major privacy violation. If you've been obsessed with a workmate or classmate, Facebook employees know. If Barack Obama's intern has been using the campaign account to troll for hotties, Facebook employees know. Within the company, it's considered a job perk, and employees check this data for fun.
Facebook has a history of protecting profiles from outsiders. The site once sent cease-and-desist letters to two of Valleywag's sister blogs for publishing certain student profiles.
The site does not allow regular users to see which profiles other users have seen. While one third-party application lets users voluntarily make their profile-visiting known, no application allows one to "spy" on the activity of an unknowing user.
Checking who's viewed a profile may be how Facebook found the tipster who violated their terms of service by sending Valleywag Steve Ballmer's profile. But were they violating their own terms?