Now that the Facebook IPO registration has been filed we can finally get real insight into their business. Key takeaway, Facebook’s ad revenue in 2011 was $3.2 billion. That represents an increase of almost 70% from 2010. We can break that down even further: part of the increase in revenues came from an increase in ad rates of 18% – not bad at all in the current economic climate – but most came from a 42% increase in ads served.

Total revenue for Facebook in 2011 was $3.7 billion – so ads represented 85% of the total – with profits of a cool and exact $1 billion. This is, if you hadn’t already realized, a very nice business: 27% net profit margins, profits up by 65% in a year and a dominant market position. SEC Registration statement here. Facebook is apparently doing quite well.