So here is my valuation of Facebook.
Based on trailing earnings of $1 billion and an expected market cap of $100 billion we get a trailing PE of 100.
As a comparison, Apple's PE is about 13 and Google's is 19.
It's really not worth spending much more time on this. Facebook is likely to be crazily overpriced.
The next question (as posed to me by my friend Robert) is : "do we short or buy puts?"