We all know that social gaming on Facebook is a multi-million dollar industry, but it could actually turn into a billion dollar industry this year, if predictions made by former DoubleClick CEO Kevin Ryan pan out, namely that Facebook will earn $1 billion in revenue from social gaming in 2011. According to ZDNet, Ryan made the prediction this week, saying that while most of that $1 billion figure will come from ad sales (those ads displayed on the sidebar of Facebook pages when users load social games like FarmVille or CityVille), a large portion could also come from the purchase of Facebook Credits.

As of right now, Facebook is a private company, and as such isn't required to report its financial information. However, with the company reportedly going public as early as Q1 of 2012, it will be interesting to learn which of these figures were overinflated, or were spot on. Either way, the very thought of $1 billion in revenue is an astronomical figure - more than enough to last FarmVille 30 million players quite a while with Farm Cash purchase, as an example. We'll be sure to stick with this story and update you when and if Facebook decides to publicly comment on the figure.

Do you think Facebook will be overvalued when the company goes public next year? Is $1 billion too large a figure, or do you think it's a fairly accurate prediction of the company's revenue for this year? Sound off in the comments.