Hitwise tweeted this morning that Facebook reached the number one most visited site in the US for the first time ever over the Christmas holiday, pushing past Google. That means pretty much Hitwise is comparing Facebook’s overall traffic to only one aspect of Google, Google web search. Potentially, some visits to Google’s personalized home page might also be in there. But also potentially, a chunk of Google traffic isn’t being counted correctly.
http://searchengineland.com/hitwise-facebook-more-visited-than-google-on-christmas-32554