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In this photo taken Friday Nov. 20, 2009, ...
AP - hace 3 horas 3 minsIn 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)
