Foursquare tops 6 million users

More than 381 million “check-ins” have been registered on Foursquare’s social location-sharing service, as more than 6 million people now have accounts there and growth for the site is higher than ever.

Foursquare says that 2010 saw growth of 3400% over 2009. That’s a number that anyone can be jealous of, though in 2009 hardly anyone had heard of the service.

Last week, the company says it registered its 6 millionth user willing to use phone GPS signals to tell the world where they are.

Hotels and restaurants were among the most popular category of places to check in from. So were train stations, because we can only assume people are so bored when they’re waiting for a train that they have nothing better to do.

The service not only allows people to let their friends know where you are, but restaurants and retailers are taking advantage of it too. Many have begun offering discounts and coupons to those who “check in” from their locations.

But it was none of these places that logged the single most popular check-in location. That honor goes to the Rally to Restore Sanity, a stunt from Comedy Central’s Jon Stewart and Stephen Colbert in which thousands of people gathered on the Mall in Washington DC to see the comedic pundits talk about random stuff. 30,525 check-ins were logged there.

Can Foursquare grow by 3400% again this year? It’s unlikely, but it doesn’t look like the service is slowing down at all.