Foursquare has announced that it has grown to 15m users, more than tripling its community in the last 12 months.

The location-based gaming platform says that half of its users are in the
US, while the other half are international, as reported by ClickZ.

This marks a year of strong growth for Foursquare, during which it secured $50m of venture capital funding  that put a value of around $600m on the company.

A blog post by co-founders Dennis Crowley and Naveen Selvadural said the cash would allow Foursquare to “move more quickly”, and the new membership stats suggest it has worked.

It has been a good couple of days for Foursquare following the announcement yesterday that its competitor Gowalla will stop operating in January after Facebook hired its staff. Though this could equally be seen as a negative, since it means the creation of one ‘super competitor’.

Plus, there’s still some doubt over how Foursquare will turn its popularity into revenue.

Some suggest that adding the ability to pay for services using Foursquare could be the way forward, combined with more deals and group discounts.

Facebook’s talent acquisition means Gowalla’s 2m users will be looking for a new check-in service, but rather ominously for Foursquare it also means that Facebook will be strengthening its location-based armour.

Foursquare’s user base of 15m users is impressive, but Facebook has 800m active users, of which 350m access the site through mobile devices.

So while Foursquare deserves a pat on the back for its continued growth, its ongoing success is clouded by doubts about its revenue streams and Facebook’s designs on a slice of the check-in market.