Earlier today, Facebook filed for a $5 billion initial public offering with the SEC and the media is now getting a chance to dig through the fairly large document to find any information the social network has revealed. 

First, Facebook revealed that it now has 845 million users, which means the world's largest social network gained about 95 million users since it last reported the number in June of 2011. In addition, Facebook revealed that its total revenues for 2011 were at $3.71 billion, a majority of which came from advertising throughout the social network. 

Facebook says that its partnership with Zynga, a social network game developer, accounts for about 12% of its total revenue, which is equivalent to about $500 million in 2011. 

Finally, Facebook describes that it also makes revenue from third-party companies paying to make sure that their locations, information, etc. appears before others on the social network. The example Facebook describes in the document filing is with Starbucks - Starbucks has the option to pay Facebook to make sure that their locations appear higher up on the "check-in" list when using Facebook Places.