AJ Bombers, a burger joint in Milwaukee, was launched in the middle of the worst recession in generations and was located at an address that had seen at least five businesses fail in recent years. The restaurant’s year-long journey from grand opening to FourSquare phenom is a best-practice example of how business can use social media to effectively drive sales. In fact, as AJ Bombers co-owner Joe Sorge points out, sales of menu items promoted on FourSquare have risen....