Facebook knows what you look like, and the implications are staggering. Drawing on billions of labeled photos, the social network will now automatically recognize faces and suggest people to tag in photos you upload. That's probably just the start.

Under the new feature, Facebook will compare faces in photos uploaded by users to "tagged" pictures in its existing database. If it gets any matches it will suggest names to attach to the new photos. A company executive tells CNET the new feature is actually a privacy enhancement, since getting tagged will alert you to "a photo of you on the Internet that you didn't know about... you can remove the tag, or you... can write the person and say, 'I'm not that psyched about this photo.'"

Right, sure. Of course, you probably won't be so psyched about this feature once it is used by, say, law enforcement to tie you to a picture of purported wrongdoing, as CNBC's John Carney imagines. Not that this is the only possible use for this technology, Those young engineers at Facebook are whip smart; give them a little time to think and they'll probably come up with something way creepier than automated global photo lineups.