Palo Alto, Calif. — Consumer Watchdog, a California-based consumer education and advocacy organization, has filed an antitrust complaint against Facebook Credits, claiming their virtual currencies used for users’ purchases in social games are “anticompetitive and unfair business practices.”

Filed with the Federal Trade Commission on Tuesday, the 28-page complaint outlines why the FTC should investigate the social networking site, objecting to new terms for using the credits that go into effect on Friday.

“The new Facebook Credits terms will enable Facebook to maintain and extend its monopoly power over the market for virtual goods purchased in social games,” the document said.

The complaint alleged that Facebook owns over 50 percent of the virtual goods market, making the multi-billion dollar company a huge revenue gain with the expected market to produce $2.1 billion in 2011 — up from $1.6 billion in 2010.

“Facebook has big plans for Facebook Credits, and its anticompetitive terms have implications beyond the market for virtual goods purchased in social games,” said Laura Antonini, Consumer Watchdog research attorney. “It is imperative that the FTC promptly investigate Facebook’s Credits terms with developers before the Facebook Credits program is expanded.”

Related Links: (Consumer Watchdog Complaint) (PR Newswire)