In a conversation with GigaOm on October 22, 2010, co-founder and CEO Dennis Crowley says that Foursquare has now passed 4 million users. According to Crowley, it took only 50 days to add 1 million additional users after hitting the 3 million mark in August 2010.
Foursquare hit the one million user mark in March 2010, a year after the service launched.
