Facebook has added two new services to its Facebook Credits virtual currency called "buy with friends" and "frictionless payments." App developers will be able to implement these features into their games, adding some small measure of enhancement above what can be done currently with proprietary virtual cash. The "buy with friends" service allows users to
spam share discounts on virtual items with friends (who are playing the same game) via the news feed. "Frictionless payments" are smaller sized Facebook credit blocks that can be purchased in small increments. This allows users to spend a little bit of money to buy 30 credits or less for the purchase small in-game items.
While App builders can still use their own currency, it is clear that Facebook wants them to get in line and get with the program. Eventually, as developers adapt to this currency, Facebook will control a massive virtual currency exchange, giving it even more power than it had before.
The end result: world domination. I suspect FarmVille re-education camps are not far off, though you can get ahead of the curve by buying FarmVille For Dummies.