Playtxt

Mobile Social Software (MoSoSo):

Playtxt: Playtxt's 6,000 members key in the postal code where they want to be found when they're on the go. Then, like dodgeball, anyone can see which friends, or friends of friends, are within that postal code." (http://www.wired.com/news/culture/0,1284,66813,00.html? )