Foursquare is “50% friend finder,” says Crowley, allowing you to “check in” at locations with your mobile device. Using a text-based field that works with the GPS skills of your phone, Foursquare narrows down your possible location and remembers it for next time. It can tell you who’s been there–helpful for navigating swarms of partygoers–and what they thought of it–helpful for knowing which parties to skip. Foursquare also plays nice with Twitter; when you check into a location, it can ping your Twitter feed.
Foursquare is currently available in 12 cities and still has a few kinks to work out (Apple approved the iPhone app about six hours before Crowley got on the plane). But just a few days into its release, Foursquare has netted some passionate users. “Someone was angry that they didn’t get their badge for going to the Digg party,” says Crowley. “He was all bent out of shape. I said I’d see what I could do.”