Untappd is a beer-sharing system. You note which beer you drank where and then watch as said beer rises or falls in the ranks of beerdom. You can also find out where odd brews have popped up in your vicinity, thereby allowing you, like some inebriated, marauding Ash in Floaroma Town, to attempt to catch ’em all.
The app itself runs on multiple devices but they’ve just announced a special SXSW version for you and yours. This allows you to compete with fellow tipplers in the streets of Austin.
If you’re thinking there’s more to this, there isn’t. Presumably you could pitch a certain beer to folks who check in, but that functionality isn’t live. It looks like a couple of dudes, tired of being ostracized for their love of the suds, have taken the necessary steps to bring their hobby mainstream. Like Beerby, the app allows you to find odd brews in odd places, a boon to the burgeoning drinker.