[acdha]

NetApps numbers appear to be based on a small number of corporate sites, which are skewed towards US media companies. They weight the numbers by the CIA World Factbook data for internet usage in a country but they've never given a reason to believe this approach doesn't exaggerate the distortions present in their sample of data.

If you want reliable numbers, nothing beats direct measurement for a comparable site. I've never worked on a site where traffic was anywhere near NetApps’ but I've found Akamai’s numbers to be reasonably close for sites which target a general audience:

http://www.akamai.com/html/io/io_dataset_v2.html