If you use Facebook, there's a good chance you've encountered some app or some friend claiming they've found a way for you to see who has been viewing your profile. Chances are, it was a scam. In fact, a few months ago, there were reports circulating about such scams. One in particular, security firm Sophos said attracted 60,000 clicks in just a few hours. Such scams still pop up from time to time. Your best bet is to ignore them, no matter how curious you are.