Zuckerberg was clear from the onset: user experience over revenue, Long term over short term, mobile is their grow space but it’s not monetized yet, and last but not least. He strategically kept the level of ownership he has in order to never worry about loosing control. Facebook is openly operating different within the public markets than analyst are used to. As I write this they last closed at $18.98, At $18.98, using the correct share count which I found to be 2.7 billion, Facebook is still valued at almost $50 billion.
Perhaps in time the longevity and the continued dominance FB maintains will calm the naysayers.