Yesterday, Foursquare launched in 50 additional cities, and yes, Buenos Aires was one of them.
What is Foursquare you ask? Well, in addition to being one of the most hyped new companies of the year, they also are a location based social network that incorporates social elements. They have a free iPhone and Android app (Blackberry coming) that allows you to “check in” from places that you are at (bars, restaurants, etc). When you check in, Foursquare will tell your friends where you are and also recommend nearby places. You can leave tips on the place you’re at and also view tips from your friends. You also earn points and badges for checking in which can allow you to become the “mayor” of a place and unlock additional freebies. You can read all the details here.
Buenos Aires is still pretty sparsely populated, so download it now and give it a try. It’s pretty cool.