What is Foursquare why should you know about it?

What is Foursquare why should you know about it?

Foursquare is not just a game you used to play at recess anymore.  It is also a location based social networking application that is worth paying attention to.  As of December 2013, there are over 45 million people on Foursquare with over 1.5 billion total check-ins...