OK I agree with datacenters but my number of indexed pages does not change 100% but 10% (9000/10000).
My boss belives that is one of the reasons why they are higher on Google ranking. I think that it doesn't make difference if you have 10000, 50000 or 10000 pages.
I can presume that their page has easily more that 50k pages if I can see results over 100k.