http://blogoscoped.com/files/google-conent-network-reach.png

Google says this table shows their content network's reach. If I understand this right, they added up all AdSense-using sites, but not Google search/ Google properties.

The full context is available in Google's new ad/ tutorial available at https://trainingcenter.google.com/gcn

What is this "Training Center" thing?

Oops, didn't answer your question.
Since there are only 3.1 billion searches conducted on Google in November in US, I don't think it's possible that Google will have 4.5 billion PVs/day, so you got that right.

Thanks for the link Philipp :)