Bartab lets you buy booze for your bar-hopping buddies… From your iPhone

Ever wanted to buy a friend a drink, but couldn’t because it was 2 in the afternoon and you were at work? Or because they’re half-way across the USA? Or because you’re so slammed you lost your wallet 3 bars ago? Well, now you can Bartab them a drink coupon. Bartab is a new iPhone, Web and Android app that lets you buy friends/girls/randoms-you’ve-never-met a drink.

With Bartab, the first app from Webtab, you pay $1 and send a friend a virtual coupon for a drink. Yes, a real drink with real alcohol. Not a Facebook gift that sits on your profile or a virtual drink you can put on your Twitter background. Hard, cold, liquor.

Drinks can be redeemed at bars around San Francisco, New York City and Los Angeles. The friend merely has to show the virtual coupon to the bartender at any of these bars, and then pay an extra $1 to the bartender. It kind of sucks that the friend has to pay the bartender, but it’s due to regulations by the state governments in CA and NY. Gifted drinks are sent via Facebook wall posts but can also be texted to the individual you send them to.

This is a great idea, but has one critical problem: it’s only REALLY valuable if a large number of venues accept the drinks. Right now, you have to buy pre-specified drinks at a limited number of venues.

If anyone has a chance at cracking the critical mass problem, it’s Bartab. Their service is naturally viral, because in order to use it you must send someone else a drink. That means that it could spread fairly quickly.

Bartab Tip #1: There’s no rule against buying yourself a drink. So if you are going to one of the locations that takes Bartab, send yourself a drink and you can drink for $2!

Bartab Tip #2: You get 6 half-off drinks just for signing up. They aren’t completely free – but you only have to pay $1 instead of $2. Solid deal.