There have been many companies that some considered to be "too big to fail" on the internet. If a decade ago you would have told somebody that America Online would be struggling to make money they would have laughed at you. If in 2007 you said that 250-million-user-strong MySpace would be all but dead by 2011, they would have called you a fool. If today you were to say that Facebook would be meaningless in 5 years people might be willing to listen this time because they've seen too many of the mighty companies fall.
Should Facebook be worried?