I don't understand why someone would google for "facebook" in the first place (or at least, more than once). I wonder how accurately the web search traffic for facebook correlates with its actual usage/popularity.
On a side note, what really boggles the mind is the number of searches for "google" or "google.com". According to the Keyword Tool, there were approximately 30mil exact searches for "google", and 7.4mil searches for "google.com"!