Created by the founders of the original location-based mobile service Dodgeball, Foursquare allows smartphone owners to “check in” wherever they are. Prospective locations run the gamut from restaurants and bars to parks, offices, and sports stadiums. But why share your location at all? Simple: Not only does Foursquare make it easy to see what your friends are doing, checking in can sometimes unlock special offers on merchandise, as well as virtual badges for better bragging rights. Cool Mango-only features include pinning a Foursquare live tile to the home screen to display current updates from friends and a slick side-scrolling interface to showcase all major functions.