In its latest move to expand on Facebook, Playdom has bought social game developer Offbeat Creations. Playdom raised $43 million last fall — it said it would be buying companies, at the time, and it quickly did with its purchases of Green Patch and Trippert Labs.

We’ve been expecting many acquisitions of this sort to happen in 2010. Smaller developers are facing a host of new competition, from big rivals like Playdom that have established traffic, experience, operations and revenue streams, and from traditional gaming companies. Facebook’s changes to its interface and platform policies — like the recent removal of notifications — means that most developers need to come up with new strategies, which is something smaller shops have fewer resources to do.

Offbeat Creations has 8 applications on Facebook, with the largest being dice game Super Farkle. Between its apps, the developer has nearly 1.5 million monthly active users and more than 200,000 daily active users, according to AppData.

The Bellevue, Wash. company, founded by Chia Chin Lee, Robert Reichner and Tom Fakes and its team of 12 will join Playdom’s 15-person Seattle office, the companies say. Terms of the deal were not disclosed.