Playdom has by far the most acquisitions so far this year among all social gaming companies, today announcing it has bought established branded game developer Merscom for an undisclosed amount.

The company previously bought Argentinean Facebook game developer Three Melons, and invested $5 million in another developer from that country, MetroGames. Today’s announcement suggests Playdom is getting serious about branded social games.  The move could put it in more direct competition with other branded game developers, like LOLapps, bringing its big team, distribution, and cash-flow to bear.

Chapel Hill, North Carolina-based Merscom has been around for 16 years, but it has been also getting in to Facebook lately, launching a relatively successful promotional tower defense-style app for “The Crazies.” From the press release today:

Founders Kirk Owen and Lloyd Melnick and their team of over 20 producers, designers, artists and engineers will lead Playdom’s efforts to partner with artists, entertainment companies and other IP holders to co-develop the next generation of social games.

“We believe that brands matter and that over time, as the social gaming industry matures, games which incorporate content from popular culture and widely respected brands will garner larger market share than those without it,” says John Pleasants, Playdom’s CEO. “Merscom has 16 years experience working with content owners and we intend to call on this experience as we move into this promising area of our industry.”

The release also says that Merscom is currently developing games for Sea World, Purina, National Geographic and NBC Universal, so perhaps we’ll see Playdom promoting those games shortly?