Foursquare launched in 2009 and reached 10 million users in September 2011. It allows users to "check in" at venues using their smartphones. In October 2011, Foursquare introduced Radar, which allows users to see friends' locations in real time. The service gamifies location check-ins by awarding badges and mayorships to users. It also provides tips, lists and special offers to users based on their location.
17. Radar( )
To-Do list Venue
3
Venue
iPhone
(iPhone 4S )
4sqWalker http://4sqwalker.com
The real world, now in real-time! Say hi to foursquare Radar!
http://blog.foursquare.com/2011/10/12/the-real-world-now-in-real-time-say-hi-to-foursquare-radar/