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Zynga, a four-year-old online company that has made its riches off selling virtual goods in social games, filed plans Friday to raise $1 billion in an initial public offering (IPO), reported AllThingsD.com.

The IPO may potentially rank among the largest of the year, especially among tech companies.
The San Francisco-based company is responsible for hit titles like "FarmVille" and "Mafia Wars." It will become the first publicly-held company to make its revenues mostly from the sale of virtual goods, like an energy boost or a buying a collectible garden gnome.

Zynga dominates the four largest applications on Facebook, attracting around 215 million monthly users. It employs 1,300 employees and has grown extremely fast, having acquired more than one company each month for the past year.

Much of its success has been tied to the ability to create games that are attractive to a large user base. Many of its early players were apparently women who were looking for a way to unplug after a long day of changing diapers, or while a young baby was napping.

Zynga and other social game makers have been largely credited with expanding the number of people who play games beyond the traditional gamers, who play on the Xbox or PlayStation.