I would think it has to do with how many other things link to the provided pages, considering that's the gist of how PageRank works. It might exclude the main

I would think it has to do with how many other things link to the provided pages, considering that's the gist of how PageRank works. It might exclude the main http://google.com http://google.com because you're doing a site search, and it assumes you've looked at the index? It might be missing most of the other pages specifically about Google because they have a lower ranking/less incoming links than the Google+ profiles listed in the search?