There's an App for that.

October 12th, 2009 - 1:22pm by Slye Fox

Ha ha. :)

October 12, 2009 - 2:30pm
damncutekitty says:

Brilliant! I would buy an iPhone just to have that.

October 12, 2009 - 6:25pm
qwangi says:

I would buy an iPhone just to have the app that blocked that one.

October 12, 2009 - 11:08pm
philady says:

Amazingly, something like that is actually in the works at MIT.

http://www.youtube.com/watch?v=ZLEEiQZOYDs

At about 3:46 in that video they show how the device recognizes people and displays things about them.