What is facebook?

A marketing research site that ropes participants in by giving them "social networking" tools. So far, 50 million people have spent their time telling facebook as much as possible about themselves. Is market research data and targeted advertisement worth $300 per person? (if one believes their $15b valuation) Certainly not for all, but probably for a small subset of those millions of users. So it all depends on how often facebook can sell the data and access to that subset.