Location-sharing service Foursquare on Monday announced that its ranks grew by 3,400 percent in the past year and that it now has more than six million registered users.
"Honestly, 2010 was just insane," the New York City-based startup said in an online post.
Foursquare lets people log their locations by "checking in" from where they are at any given moment using smartphones or other Internet-linked devices.
Satellite location tracking capabilities of smartphones or mobile signal tower triangulation lets Foursquare estimate where members are when they check in.
People's whereabouts and text comments, if any, are then shared with selected circles of friends at Foursquare.
Foursquare rewards users with virtual "badges" for accomplishments such as traveling to distant places or frequenting boats or trains.
Some businesses have started offering deals to Foursquare users who check in on premises.
Foursquare said its six millionth user signed up last week. During the course of last year the service logged check-ins from every country and one from an astronaut in space.
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