The people who make FarmVille, CityVille and Empires & Allies think their company's stock will be worth at least $US1 billion when they go public. The New York Times thinks the company's value could go up to $US20 billion.
However it adds up, Zynga is clearly a huge player in modern video games. How do they compare to those other giants in video games?
Here is the market cap for the biggest players. Market cap may not be the perfect way to measure how much a company is worth (it's the number of shares multiplied by the share price), it does help put things in perspective.
At the low end, Zynga is in the same league as Ubisoft. At the high end, it's almost Nintendo-sized.
All market cap figures via Marketwatch