A better argument would be that Facebook's valuations are being driven by large amounts of investor money injected into the Zynga symbiote, who throws nine figures a year at Facebook to continue identifying new pieces of brain matter to feed to their mad cows. I don't think that is a great argument, both because Ponzi schemes are not the kind of racketeering one should be worried about if one is worried about there, and because I think that Zynga is probably sustainable. They may be the only business on Facebook whose advertising is sustainable... but that would, by itself, justify a gigantic valuation for Facebook. (Perhaps not any particular valuation.)