It appears that Foursquare has just passed 5 million users if new user account numbers are correct.
It’s taken just a month and a half for the location-based social network to accumulate one million more members. It took the same amount of time for Foursquare to reach four million members and for the network to hit 3 million users.
Some thought Foursquare would be doomed following the debut of Facebook’s location-based feature, Places but the services could be complimentary as the Places API, the feature serves as a platform for services like Foursquare and Gowalla. And Foursquare founder Dennis Crowley reported that the network had its biggest day of signups following Facebook’s announcement. And Crowley told the LA Times in August that the startup is growing at about 180,000 users every 10 days.
It took only two months for Foursquare to add 100 million check-ins to its service to reach a total of 200 million check-ins. It took them about 16 months to reach 100 million check-ins. Other signs of growth—Foursquare is hiring and just opened a West Coast office.
Of course, it’s unclear how many users out of the 5 million members are active, which would be a true indication of how fast the network is growing.