Have a rare brew you love, but can never find? Untappd makes tracking that beer down effortless. Users search for beers they're drinking by tapping "Drink Up," and instantly gain access to reviews of the beer and where people are drinking it. You can also "check-in" to individual beers, essentially creating a running list of what you've drank and when. Based on your drinking history, the app can then make recommendations on beers you might like, as well as alert you to brews trending nearby.