It's PURE speculation, IMO. For a company that MIGHT earn $2 billion this year to be valued at $70-100 billion is utterly ridiculous. Put another way, Apple earns more in about a week than Facebook earns in an entire year. And Apple is currently valued at $370 billion, on a price earnings ratio of about 16. Even if you said Facebook is growing faster than Apple (which I don't know that its revenue or earnings is) and gave Facebook a 20 P/E ratio, that still only gets you to it being a $40 billion company. When a company that doesn't make a product, just a (fad, IMO) service, gets a P/E of 35-50, I think that's completely crazy. But I won't short it when it goes public. Even though I think it'll eventually come back down to earth, if it gets a $100 billion valuation when it goes public, the suckers and Facebook fanbois might drive it higher for awhile.