In-Q-Tel, the venture capital arm of the CIA, has invested in a number of companies specializing in facial recognition, and has also been closely involved in Fa

In-Q-Tel, the venture capital arm of the CIA, has invested in a number of companies specializing in facial recognition, and has also been closely involved in Facebook's funding. If you set aside all the conspiracy theories you can generate from that fact, it's actually kind of cool. Comparing a person's face against a homogeneous collection of millions other faces is an intractable problem. If you place the search in the context of the social network, however, it becomes much simpler - assuming it's not some random face in the background, you probably only have to travel out a couple degrees of separation to find a probable match. Even if it is a random face on the street, you're aided by the geographical context. I think Facebook is generally more hype than substance, but they do leave the door open for some pretty interesting ideas.