As far as i understand about the valuation of Facebook company, the key revenue drivers shown by Mr damodaran was exactly right, but there are two more main points to consider i.e how many genuine active users they have as well as how much time there is no such social networking site in this competition.
This sort of thing can happen in racing and Ihave to try and look on the bright side: eight points is still a good amount and the one-two finish is great for the team.