In this photo taken Friday Nov. 20, 2009, the Foursquare application is shown on an iPhone in front of a Starbucks in San Francisco. Foursquare lets you share your whereabouts with friends, no matter if you’re at a hot new bar or a neighborhood pet store. (AP Photo/Russel A. Daniels) Original Filename: Social_Interaction_Startup_FX101.jpg
