The latest "get rich quick" plan apparently involves cultivating an audience of app users on Facebook.

Playfish became the latest developer wooed by the acquisitive siren song of a larger industry colleague. Electronic Arts (NASDAQ:ERTS) is buying the social-gaming specialist in a $275 million deal, which could be worth as much as $400 million in equity retention arrangements and performance-based earn-outs.

Playfish entertains 60 million monthly active players across its multiplayer diversions, driving more than a billion gameplay sessions along the way. Its sticky apps run on Apple (NASDAQ:AAPL) iPhones and News Corp.'s (NYSE:NWS) MySpace social network, but its real drivers are Facebook hits Pet Society, Restaurant City, and Country Story.

This isn't the first time that a public company has snapped up a rising star on Facebook's platform. Expedia (NASDAQ:EXPE) and The Knot (NASDAQ:KNOT) gobbled up the makers of travel and wedding planning apps, respectively.

The monetization of social apps remains a work in progress, but the traffic trend is undeniable. Facebook is becoming a bigger part of the lives of its 300 million -- and counting -- users. In EA's field, video game hardware and software sales have fallen in six of the past seven months. Diehard gamers are still a loyal lot, but the video game industry needs to reach the broader mainstream audience. Right now, those people are on Facebook, playing Playfish's Restaurant City and Zynga's FarmVille.

EA is doing the right thing by acquiring Playfish, but this is still a nascent industry with a thin moat. The low barriers to entry will make social networking games even more competitive in the coming years, making it that much harder for even the heavy hitters to crank out viral hits at will.

EA needs to be here, but the cover charge sure isn't cheap.

Are Facebook apps a passing phase? Can social gaming be effectively monetized? Share your thoughts in the comment box below.