Buying someone a drink is a timeless gesture, and the best part about it is, they automatically have to sleep with you. Buy that lucky partner's next one from the comfort of someplace far away, where you don't have to get nice with them, with Bartab.
San Francisco-born, just-hitting-ATL Bartab gives you an excuse to actually buy people drinks, and everyone else an excuse to do the same for you, all from your phone, and all incredibly cheaply: someone just has to pony up a dollar to "reserve" the drink at a participating bar, then the lucky recipient heads in and gives them another buck, probably Michael Redd, as he's not up to much these days. To buy for a buddy, use their app to scan participating joints and their deals, including a beer-of-the-day at HOBNOB or a Numbers Ale at TAP, Stoli cocktails and whiskey-gingers at Republic Social House, and a glass of Gundlach Bundshu merlot at ONE -- take advantage of them all, and you'll believe your work is done, until you remember that you're Brian McKnight. To retrieve a round reserved for you, go to 'My Drinks', click the 'Claim This Drink' tab, and show the bartender your activated coupon; once activated, you've got five minutes to claim your bev, so they provide a handy countdown timer, the not beating of which will make you feel like the Worst Person In The Worrrrld.
Stupid-phone users can participate via the Facebook/SMS function, which sends your drink deal via text and gives you 90 days to claim it. The only catch for any phone: you get only one drink per bar, per day, and only one drink per hour while bar-hopping, meaning you can only have sex like five or six times per night or something, but whatever, it should be nice.