The latest addition to the ever-growing lists of constant-contact facilitators is Foursquare , recently profiled by The New York Times . Users of the social networking site can share their current location with friends in real time. The free service is designed for use on the go, and in addition to its web-based presence has BlackBerry and iPhone applications available for download. To read how Foursquare works and to share your thoughts, .
The service is based on check-ins: when you arrive at a location (a restaurant, store, bus stop, wherever), you "check in," disclosing your location to friends. Check-ins earn you points; a series of check-ins at certain places (three places with a photo booth or 50 unique venues, for example) earn you coveted merit badges. Add tips and to-do lists with any location, and read other Foursquare users' tips and lists when checking into a new place. This isn't a new concept — Foursquare founders built the idea from Dodgeball, a now-defunct service that used SMS messaging to alert friends of your whereabouts. And services like Latitude and Loopt  provide similar location-based services.
Foursquare launched in March and is now available in 35 cities from New York to Vancouver to London.
Do you use Foursquare? Do you think it encourages oversharing, or is it a helpful way to keep tabs on friends?