Facebook's got a series of changes to its terms of service. The most interesting bit is the they want to start using your profile photo as the basis for suggesting that you be tagged in your friends' photos.

So what it means is that your face is not an actionable piece of data that they can use to associate with your identity.

Facebook has only posted a section-by-section summary of the changes has been posted, but the actual tracked changes document isn't online yet that we can see.  ATD has the relevant section in its news post:
We are able to suggest that your friend tag you in a picture by scanning and comparing your friend’s pictures to information we’ve put together from your profile pictures and the other photos in which you’ve been tagged.
The old language:
We are able to suggest that your friend tag you in a picture by scanning and comparing your friend's pictures to information we've put together from the other photos you've been tagged in. This allows us to make these suggestions.
More facial recognition to come. Oh yeah.