Because we all over share! Keep your friends and followers constantly updated by sharing that you farted, how smelly/loud/wet it was and where it was. Check the map to see where your friends passed through and passed gas, sharing it all is the next frontier in social networking.
In a world, endulged in network culture, the modern narcist is able to share each and every step he takes, literally.
The ‘social network’ Foursquare enables its users to check in to places they visit, registering them as a guest there until they check in at a different venue. By checking in, users receive points, and thus become players in the city wide location based social game, competing with one another over who receives ‘Mayorship’ of venues.