Social City creator Playdom accepts Facebook Credits exclusively across all games

Just like that, the final domino falls. Playdom is the next company to submit to Facebook's demands for social game and app developers to accept only its virtual currency. As of today, Playdom will only be accepting Facebook Credits as its virtual currency. Fortunately, the company will, of course, still accept credit and debit cards as well as PayPal payments.

If this deal is anything like Facebook's previous three, we imagine Playdom will have to deposit 30 percent of all Facebook Credits sales into the social network's bank account. It also bears mentioning that the unique currencies to Playdom's games like City Bucks in Social City and Campus Cash in ESPNU College Town aren't going anywhere; it's the third-party payment methods that are officially kaput. And thankfully the free offers from Playdom's ad partners for in-game money don't seem to be going anywhere either.

This isn't the first time Facebook has coerced social game companies into using its new currency, which is now available at GameStop and Radio Shack in addition to nearly all major department stores. With CrowdStar the first to go and later Zynga giving in, it was only a matter of time before EA and Playfish accepted the offer too. Finally for Facebook, the company will be reeling in 30 percent of the top four social gaming companies' profits via Facebook Credits. Let that one sink in for a while and you'll understand why Zynga might want out.