Athiests can you explain why Facebook stock is worth $164billion when total health care cost is $300billion?

[sanity]

Facebook, Google, Yahoo, Baidu, etc, derive their income from advertising revenues. If no one uses Facebook anymore, its value would instantly crumble. Market capitalization is not equal to what a company actually has, in terms of actual assets (in dollars) at the moment in time but on the expected revenues it might get in future. That's why we sometimes see Apple's shares going up to $800 but might fall to less than $500/share in any period of time or to even lower level.
During the financial fiasco of 2008, stocks prices lost more than $6 trillion in value. That is to say that the actual worth of those stocks was actually not so much but buoyed by market perception and when the bubble burst, it more or less went back to the equilibrium value.