We've been hearing about this for a while and now it's finally here. Facebook has launched Facebook Deals, a Groupon competitor, in five cities: Atlanta, Austin, Dallas, San Diego, and San Francisco. Now that it's here, some details are being filled in. First, it's all done through news feeds and not through email like Groupon does. This makes it more social, more public, more about sharing, more in line with Facebook. Secondly, it doesn't work on real money, it works on Facebook Credits. I think that point is dramatically important. If people don't like the idea of buying credits only to spend them again, the whole service will just seem like too much of a pain in the neck and Deals will wither, consigning Facebook to its own social networking lane forevermore. But if it works, Facebook has a legit new currency that it controls, which makes it a couple steps short of being a new world government. Stay tuned!