Twitter's great and all but the Technorati needs to feast on a new dish. You know how it is. According to AppScout, Four Square is the entree of choice at the South By Southwest/Interactive this year. This year's breakout story is sure to be a social network called foursquare, from the guys behind the now-defunct Dodgeball social-location service. Users "check in" from wherever they are on a given night, pinging …