Well, it does not matter what the factors taken into account were. I certainly am not surprised that this happened. After all, majority of the people who go online especially the teeny boppers have a Facebook account and they spend much of their time socializing but that is all there is to it.
They can use Facebook to search for anything related to people and it is only up to that. Google still reigns supreme when it comes to search factor. Take the case of a programmer. Do you think one would use Facebook to search for solutions or possibly some source code that he could reuse?
Facebook may have won the traffic challenge versus Google but Google’s popularity in the search engine field will always be strong and will never diminish. Facebook challenged Google where it is weakest: online identity and the social Web, and won. After all, it is what Facebook is all about. But other than that, Google still reigns supreme.