iPhoto has face recognition software. You put a name to a face on a photo, and then it hunts through your library for matching faces. I named myself and let it go, and it works freakishly well. It identified me as Indiana Jones. It identified me with the Doctor Orpheus beard. Mouth open, mouth closed, blurry... it made no difference to Skynet.
But it's not perfect... It also guessed that I was
ian_tiberius (twice),
popepat,
vadenalim, and, ahem,
casketgirl, as well as PalaeoMorgan dressed as the Monarch.
Must be the eyebrows.