who algis budrysIf you thought Facebook knew a lot about you before, wait until it recognizes your face.

The company published a blog post this afternoon announcing a new feature called “tag suggestions,” which use face recognition technology to suggest which friend is probably featured in which photo. So when you upload a big batch of photos, Facebook will group similar faces together, because they’re probably photos of the same person. It will also look at past photo tags to suggest who the person in the photo might be.

This sounds like a big step forward from the face detection feature that Facebook launched in July, where the site found the faces in a photo and selected them for tagging, but it didn’t do anything to suggest whose faces might be featured. If the new tag suggestions work as planned, they could be a threat to startups like Face.com, which offers its own face recognition apps for Facebook users — but at least Face.com extended its technology beyond Facebook earlier this year.

The social networking site is pitching the new feature as a way to make tagging easier, especially when you upload a big photo album and have to tag the same person over and over again. I don’t think Facebook Photos were suffering from a dearth of tags, but it makes sense for Facebook to streamline this process as much as possible — the company has credited the tagging feature for making Facebook the most popular photo site around.

I’m betting that some users will be uncomfortable with this idea, especially if there are embarrassing photos of them on Facebook that they’ve hidden by un-tagging themselves. This new feature shouldn’t do anything to affect your ability to do that, but it might still be disconcerting to realize that Facebook has the technology to know that you’re in the photo, tagged or not.

Facebook is trying to head off privacy concerns by giving users an option to turn off the feature so that their names are never suggested when their friends tag photos. And users will have a few days to get used to the idea before they see it live, because it doesn’t roll out until next week.

facebook tag suggestions