By all measurements, check-in social service Foursquare is having a great run: it not only added its 6 millionth user this month, but also slammed the lid on 2010 with 381,576,305 check-ins, a 3400 percent increase from the year before.

For all the chatter, though, the numbers may deserve bit more scrutiny. Read Write Web's Audrey Watters points out that all those badges people have been earning aren't because masses of people have been announcing they've done anything remotely cool. Instead, the majority of traffic consists of people logging in "throughout the day, most often for food, work, and shopping."

Of course, that's nothing to sniff at, considering that people have checked in from space and North Korea.

Check-in quality aside, Tech Crunch's Leena Rao notes that for now, Foursquare owns this element of social networking. In fact, Rao says Facebook's attempt to enter the space only pushed Foursquare's success to greater heights.

RWW's Waters, meanwhile, notes that "some people have questioned whether the notion of the 'check in' will ever become mainstream. ... Certainly," she says, "there can be a number of things that motivate us to do so--and could lure new users to location-based social networks." That said, for now "our Foursquare check-ins seem pretty banal."