Social games giant Zynga, the company behind titles such as Farmville, has just filed its S-1 form to go public, with the intention to raise $1bn.

The move has been expected for some time and sees the firm join LinkedIn, Groupon and Pandora in a wave of tech IPOs this year. The company lists its bookings and revenue for 2010 at $838.9 million and $597.5 million respectively, representing an increase from 2009 of $510.8 million and $476.0 million respectively.

What’s most interesting about the filing as we read through is the picture it paints of a company at the behest of Facebook. Although Zynga has its own websites, much of its engagement is through Facebook apps and that shows in the filing:

Our business would be harmed if:
Facebook discontinues or limits access to its platform by us and other game developers;
Facebook terminates or does not renew our addendum;
Facebook modifies its terms of service or other policies, including fees charged to, or other restrictions on, us or other application developers, or Facebook changes how the personal information of its users is made available to application developers on the Facebook platform or shared by users;
Facebook establishes more favorable relationships with one or more of our competitors; or
Facebook develops its own competitive offerings.

It goes on to note that: “A significant majority of our game traffic is hosted by a single vendor and any failure or significant interruption in our network could impact our operations and harm our business.”

The company also notes its need to pick up the pace in the mobile area, where it is only just starting to find its feet: “Our growth prospects will suffer if we are unable to develop successful games for mobile platforms.” The key importance of founder and CEO, Mark Pincus is also noted: “If we lose the services of our founder and Chief Executive Officer or other members of our senior management team, we may not be able to execute our business strategy.”

Much of the financial detail in the filing is currently incomplete, so expect more to emerge on this story soon with regard to Zynga’s current financial situation. We’d expect the actual IPO itself to still be some months away.