Via the Economist: 

AFTER eight years, scores of lawsuits and a blockbuster movie, Facebook is going public. It is seeking to raise $5 billion from its initial public offering, which would give it an estimated market capitalisation of $80-100 billion—similar to that of fast-food chain McDonald’s. The social network employs only around 3,000 staff, giving it an average revenue of $1.2m per person in 2011. Analysts are quick to point out that the site’s users effectively act as employees, adding content and value for others.