Zynga, the social gaming giant behind "FarmVille," has just been valued at $5.5 billion by SharePost, the service which exchanges shares of privately held companies such as Facebook, Twitter and Zynga.
Nintendo remains the top publisher.
Zynga was launched four years ago and mainly uses Facebook to distribute games. With a built-in audience of 500 million, the company has ascended very quickly thanks to FarmVille, FrontierVille and others. The company makes money off virtual goods, like weapons and upgrades that advance in-game play.
The company has about 210 million monthly active users.












