Foursquare Celebrates 20 Million Users, 2 Billion Check-ins with 2012 4sqDay Badge

Foursquare‘s location-sharing service has reached 20 million users who have posted 2 billion check-ins, according to a report by VentureBeat.  The New York-based company is currently celebrating its third annual Foursquare Day in honor of today’s date (which corresponds to the number four, squared) with a new 4sqDay badge for anyone who checks in with the service.

It’s not an easy day to spell, but the concept is simple:

In 2010, foursquare fans declared April 16 4sqDay (4/4^2 – nerds after our own heart!). Two years and two billion check-ins later, you’re still why we get out of bed each day. Thanks to all 20 million of you for making us part of your lives. Happy 4sqDay!

At the end of February, Foursquare had 15 million registered users who had checked in 1.5 billion times at places like restaurants, museums, and parks. The company integrated with Facebook’s Timeline on March 16, which might have helped grow its user base and made the check-ins easier to share.

To celebrate, the company has a bunch of parties planned in cities all over the world. In this video, you can watch the entire Foursquare team in New York, London, and San Francisco thank their users as they pass around a rubber ball.