photo credit:Pierre Mallien via photopin cc

How many Facebook friend requests have you denied because you don't know the person? Does it happen regularly? Yeah, you're not alone.

The New York Times had an article today about a growing trend on catching would-be-criminals: "catfishing." A police detective creates a fake persona, usually a teenage girl, and starts sending out friend requests to get leads. Welcome to the world of cyber crime fighting.

So that random Facebook friend request may not be so random after all. But that doesn't mean we should let our guard down. In a social network of about a billion people how many of these accounts are fake? Facebook estimates 8.7 percent, or 83.09 million accounts.

If you think you've been targeted, Facebook even has a quick page to report the fake account.

Moral of the story: just like in "real" life, make sure you know who your friends are!