Location-based services such as Foursquare and Gowalla use internet-connected mobile devices’ geolocation capabilities to let users notify others of their locations by “checking in” to that location. Location-based services often run on stand-alone software applications, or “apps,” on most major GPS-enabled smartphones or other devices.

Some of these “geosocial” services emphasize social networking functions, and can notify friends on the service when the user is nearby. Users may also be able to leave comments or reviews for a certain business or other location, which may be viewed by later visitors. Other services take a gaming approach, in which check-ins are used to unlock “levels” or “badges,” or can be used to earn a certain title (such as “Mayor”) when the user has checked in to that location more than any other user. (Here the mobile device’s GPS function is also important to help prevent people from checking in to places they are not at physically, which is considered a form of cheating.) Such detailed real-time information about customers’ habits is very attractive to businesses, who may share special deals with users, or reward “mayors” and other frequent users with free or discounted services.