The original dot.com bubble was about flipping shares of stock for companies that NEVER made money and could NEVER make money. While Facebook does make a profit, it is a tiny one compared to the valuation of their stock. IPO's were supposed to help small companies finance major expansion to be come large profitable companies, FB did an IPO for no apparent reason other then to cash out, they have no plans for that cash at all. Anyway when you have billions of dollars in money rolling in from 401K's every year you have to buy something, which is why pretty much all stocks are over rated.