Dennis Crowley, co-founder of Foursquare, the social network and nightlife "check-in" game that connects friends via GPS, is in his underwear. On the roof of a 20-story building. In the rain. He dutifully steps into a hot tub containing six people who appear to be in advanced stages of intoxication and poses for a picture. After the photographer is satisfied, Crowley climbs out, wraps himself in a towel, and announces there is "nothing to see here, everyone."
The six tipsy hot-tubbers flirt. The 30 visibly inebriated people on the roof keep throwing back beverages. Crowley disappears downstairs into the Hotel on Rivington penthouse, a glass-walled event space in the Lower East Side with breathtaking views of Manhattan. From about 10 p.m. to 2 a.m. on this night, April 16 -- 4/16 (four plus its square, get it?) -- the room is bursting with Foursquare enthusiasts, an eclectic mix of programmers, students, media scenesters, and social butterflies.
The planning for the party started last month when Foursquare superfans in Tampa, Florida, realized the significance of the date and declared it a holiday. Pockets of Foursquare enthusiasts around the world began organizing parties -- 150 of them -- in anticipation. By the time "Foursquare Day" rolled around, Pepsi and Atlantic Records had jumped in, sponsoring a hip-hop dance party at the Rivington in honor of the popular social game, and the Foursquare crew themselves planned to attend. Free booze, red-carpet treatment, and a posh penthouse awaited those who managed to check in.
"It couldn't get nerdier than this," says Brandon King, a 31-year-old Foursquare enthusiast from Ohio. "But hey, nerdy is the new black."
Muscly bouncers shove new arrivals back down the elevators they came from, shouting things about fire code, which the party threatens to violate (400 people by my estimate). Asked earlier how many people he expected to attend, Crowley said, "As many as will fit in. It's a good thing you got here early."
The only people dancing are two girls near the wall. And they're going at it with reckless abandon. It turns out they're crashers who have no clue what Foursquare is. "Hang on," one says after hearing an explanation of the smartphone app that uses GPS to reward people for reporting their locations -- checking in -- with freebies, boy scout-style virtual badges, or titles such as "mayor." "So no one here knows each other, but they came here because they all have an iPhone app?" she asks. Exactly.
Thirteen months after launching in March 2009, Foursquare has approximately 1 million users. The majority of them joined since New Year's. Four months ago, Foursquare threw a party on the roof of the nearby Cooper Square Hotel. But most of the partygoers were personal friends of Crowley and his team. Several people from the fashion industry and Wall Street interspersed among the techies, a testament to Foursquare's broadening appeal. But only about 100 people showed up to chat about Ruby on Rails and other nerdy topics.
Since then, Foursquare's user base increased five-fold (from 200,000 to 1,000,000 users), and it's managed to steal the spotlight from established networks like Loopt and Brightkite and upstart competitors like Gowalla. "Foursquare has a personality that's fun to interact with," explains New York resident Leslie Forrester. "This identity makes it funner than the other ones." Brandon Keene, a 24-year-old Foursquare user at the party, adds, "It's interesting that users are so passionate about Foursquare that they threw this party for them, rather than Foursquare throwing it themselves. People are obsessed with Foursquare. It's kind of ridiculous."
The growth in Foursquare over the last four months is directly proportional to the growth in size of its parties. And judging by the line snaking out the Rivington's door and around the block on a rainy Friday night, Foursquare founders are having their rock star moment. Hundreds of twenty- and thirtysomethings stand in the chilly New York drizzle, waiting for a chance at bumping shoulders with Crowley and downing a few free Coors Lights in honor of an iPhone app. Even Kevin Rose, CEO and founder of the social news site Digg -- and an early investor in Foursquare -- can't immediately get in. His blue VIP bracelet doesn't persuade the bouncers one bit.
Crowley heads downstairs to hang out with the people in line for a while. He directs them to the "spillover party" he's declared at the bar next door. A few moments later, he's back upstairs at Rivington, getting his photo taken in front of a Pepsi backdrop while French DJ duo Justice's raucous banger "D.A.N.C.E." thumps at full blast. He's wearing a gray T-shirt and jeans, as under-dressed as anyone at the party. "I came straight here from work," he explains.
Paramendra Bhagat, an entrepreneur and Foursquare user at tonight's party says he started using Foursquare in February, when user activity started picking up dramatically. "When people say Foursquare is the next Twitter, I believe it," he says.
Clearly not everyone is a user. Of the 500 or so people at the party Friday night, only 116 were actually checked in on Foursquare after midnight. (To be fair, though, there were another couple hundred who checked into "The Line" or the party at the bar next door). The number of people also checked into the party on Foursquare's chief rival, Gowalla: four.
Photos: Vadim Lavrusik