How does Facebook make money?

Facebook filed its IPO this week and confirmed what many of us already know: Facebook makes most of its money by selling ads on its site. In fact, in 2011, 85% of their revenue was made via advertising; the remaining 15% made by payments and other fees.

Compared to Google, which gets 98% of its revenue from advertising, Facebook is more diversified. In one years time, Facebook is making 10% less from its advertising space, gaining funds from other avenues.

Interesting tidbits:
Who is the driving force behind Facebook’s payments business?
Zynga, the company that makes FarmVille and other popular Facebook games.

Which company bought $3.8 million worth of advertising on Facebook last year, representing 0.1% of Facebook’s total ad revenue?
Netflix.

Which company bought $4.2 million worth of ads from Facebook last year, also about 0.1% of Facebook’s total ad revenue?
The Washington Post

Which two companies have have officers who are on Facebook’s board of directors?
Netflix and The Washington Post