(Thanks to NoCamels) Israeli startup ListNPlay has developed an app called EQuala that enables users to create a personalized music stream based on the musical tastes of their friends. It is claimed to be the first true social radio.
http://nocamels.com/2013/04/equala-uses-your-friends-to-build-a-customized-radio-station/
http://www.youtube.com/watch?v=CUj2ibps7R4&feature=player_embedded