The fact that Google is trading on the open market, as compared to Facebook's makes these two valuations hard to compare directly.
SecondMarket aside, when valuations are based on participants (insiders & investors) who have no reason to be skeptical/down-to-earth (is there any way to "short" a startup and affect it's valuation?), they are bound to be somewhat exuberant.
SecondMarket aside, when valuations are based on participants (insiders & investors) who have no reason to be skeptical/down-to-earth (is there any way to "short" a startup and affect it's valuation?), they are bound to be somewhat exuberant.