“Because photos are such an important part of Facebook, we want to be sure you know exactly how tag suggestions work: When you or a friend upload new photos, we use face recognition software—similar to that found in many photo editing tools—to match your new photos to other photos you’re tagged in. We group similar photos together and, whenever possible, suggest the name of the friend in the photos”.
And the site is proactively building in a privacy option in case you want to make life difficult for your friends by not allowing them to use the beauty of technology to quickly tag their photos:
If for any reason you don’t want your name to be suggested, you will be able to disable suggested tags in your Privacy Settings. Just click “Customize Settings” and “Suggest photos of me to friends.” Your name will no longer be suggested in photo tags, though friends can still tag you manually.
Don’t worry, you can still escape your terrible and/or embarrassing photos on Facebook. The Facial Unrecognition Technology that is the “untag” option will remain in effect.
Of course, there will probably be a broader Web image search at some point soon that incorporates this technology — a Google or Yahoo image search based on your particular face instead of just your name — and at this point, there’s no “untag” option on the World Wide Web. New photo pose instructions: “Smile and say, ‘Cheese… and please don’t upload this to the Internet if it’s a bad photo of me.’”