Well...Facebook's IPO valuation was about 100 billion US dollars. So if Facebook generates 100 billion dollars in profits throughout its history, inflation-adjusted, IPO investors who hold onto their shares will get their money back. Otherwise, their gamble will not have paid off. There won't necessarily have to be any fools anywhere.

I'm not so sure about that. Facebook is WAY overpriced. It will take years to recoup the costs and they have very few prospects of making money in the forseeable future. I support your theory that Facebook will make 100bn back, but by the time Facebook does, the 100bn will be worth far less than that amount, due to potential earnings.

As an example, I bought Qantas shares a while ago - and held them for 10 years. Their value didn't go up much in 10 years, so the "potential" earnings of that money was not realised - so despite the shares not going backwards, I lost out.

Facebook is a losing proposition, unless they pull a rabbit out of the hat - and there's nothing on the horizon at all that even indicates they will come up with something.