Facebook had revenues of up to $800 million in 2009, according to Reuters. Some quite obvious drivers of revenue growth last year:
* User and traffic growth
* A targeting system (age, geography, interest) that makes sense and allows smaller and larger advertisers to get started and find advertising that works on a CPA and optimize advertising campaigns. Combined with cost-per-click payment it is low risk to start advertising
* Zynga and other makers of Facebook games marketing their new games
With about 500 million users, a growing ad sales operation and a new micropayment system, Facebook will likely grow very quickly in 2010 too.