Actually the social gaming companies that are actually hauling any real money in (IE Zynga) sell their credits themselves. You either pay Zynga directly by credit card, or you can pay indirectly through paypal. Those are the only two options, but as for games on facebook the points are still only going into a single game and cannot be used in different games by one developer, or in games by different developers, like a facebook controlled 'currency' could.

Essentially, it would be if Apple didn't allow you to put money onto your account. You instead have to use your credit card to make a transaction on every single song purchase. It would be stupid, and Apple wouldn't make nearly as much money as it could.

> We’ve found once you get into these digital-only goods and services there’s massive opportunity for fraud. We couldn’t find a single company that could manage or solve that problem for us. We had to build the whole infrastructure in-house. We had to go out and get relationships with credit-card processing companies. - Mark Pincus

Facebook would have a unique opportunity to step in and dominate this market. If Zynga cannot control these transaction companies, how can smaller developers? Like I said, tapping into this market could mean Facebook could not only boost revenues to many of these social gaming companies, but it could be taking profits off of every transaction. 5/6ths of Zynga's users are from social networking sites, meaning Facebook could easily take profits from 5/6ths of Zynga's users by being trustworthy. There are then plenty of other developers in the market, especially thousands of smaller developers, who could make Facebook hundreds of millions that they're not tapping.