Foursquare, stylized as foursquare, is a location-based social networking website for mobile devices, such as smartphones. Users “check-in” at venues using a mobile website, text messaging or a device-specific application by selecting from a list of venues the application locates nearby.[3] Location is based on GPS hardware in the mobile device or network location provided by the application. Each check-in awards the user points and sometimes “badges”.

via Foursquare – Wikipedia, the free encyclopedia.

The service was created in 2009 by Dennis Crowley and Naveen Selvadurai. Crowley had previously founded the similar project Dodgeball as his graduate thesis project in the Interactive Telecommunications Program (ITP) at New York University. Google bought Dodgeball in 2005 and shut it down in 2009, replacing it with Google Latitude. Dodgeball user interactions were based on SMS technology, rather than an application.^[4]