PALO ALTO, Calif. (KGO) — The Consumer Watchdog organization has filed a complaint with the Federal Trade Commission accusing Facebook of violating antitrust laws through the use of its currency system, "Facebook Credits."

Consumer Watchdog is also targeting the deal between Facebook and game developer Zynag as another alleged unreasonable restraint on trade.

Zynga is the producer of most of the games played on the popular social networking website.

The virtual goods market is expected to produce more than $2 billion in revenue in 2011.

Thirty percent of Facebook's 500 million registered users are in the United States.