Yahoo! Files for Patent on Geo-Located, Social, Augmented Reality

You're walking down the street. Your phone buzzes, a map or a screen overlay pops up and you're shown a note left in that location by one of your friends - along with an ad for your favorite pizza. Walk into the pizza place and your phone buzzes again - your friends have something to say about the guy behind the counter. That might have sounded far-fetched a few years ago, but it doesn't so much anymore, does it?

http://www.readwriteweb.com/archives/location_social_augmented_reality.php