Foursquare: Still Not a Passing Fad

In March 2010, Foursquare had 750,000 members; today, Foursquare has over three million users.  This rapid growth was thought to slow with the introduction of Facebook Places a couple of weeks ago, and instead, it was the day that Foursquare had its largest registration day ever.  (source: Mashable)While three million is just in a drop in the bucket compared to Facebook's 500 million users worldwide, it is not something to ignore, either.