By now, you've most likely noticed the many apps and Web services claiming to let you see who's viewing your Facebook profile. Is your college ex checking up on you? Is someone from work scrolling through pictures of your beach vacation? Are your parents secretly peeking in on your private life? These apps promise the answers.

Unfortunately, they don't deliver. Not a single one of them.

You can be 100 percent certain that each and every app that says "See who views your profile!" or "stalker tracker" or anything else like that is virus-laden junk. These apps would like you to cough up your Facebook password, or they might install the ability to spam your friends via your Facebook wall.

Again: Be extremely wary of any service or app that claims to show you who's been viewing your Facebook profile. This functionality violates Facebook's privacy rules. If you've fallen prey to a purported stalker app (or any other type of Facebook malware), be sure to check out Facebook's instructions for revoking app access to your account.

That said, there are a couple ways to get clues and insights into who's been floating around your profile. You won't end up with the definitive list you're likely looking for, but keep reading for tips and tricks that toe -- but don't cross! -- that fine line between natural curiosity and a massive breach of privacy.