Dodgeball, a mobile social networking application written by two students of NYU, was acquired by Google yesterday. The service is available in some 22 cities in US (So now I know why I hadn't heard about it).
From their FAQ:
The idea is simple: tell us where you are and we'll tell you who and what is around you.
We'll ping your friends with your whereabouts, let you know when friends-of-friends are within 10 blocks, allow you to broadcast content to anyone within 10 blocks of you or blast messages to your groups of friends.
For example... You're having drinks at Luna Lounge. Send a text message to firstname.lastname@example.org with the message "@Luna Lounge" and we'll send out a text message telling all your friends where you are AND send you back a message letting you know if any friends-of-friends are within 10 blocks. If you have a camera phone, we'll even send you their picture.
It is upto the user to inform his current location by sending a text message to Dodgeball so the service can be used from any phone that supports text messaging. Interestingly, there's nothing on the Google Blog about it. I wonder if they have plans to integrate Dodgeball with Orkut and offer the service at more places around the world.