As of Feb. 21, 2001, Yahoo! generated 39.62 percent of all search engine referrals worldwide. Google was second with 12.08 percent, followed closely by MSN (10.92 percent), AOL NetFind (6.33 percent), and AltaVista (6.31 percent).
From Statmarket's page on method: "While the 200,000+ Web sites worldwide that HitBox monitors are self-selected, StatMarket's figures are culled from more than 50 million unique visitors who visit those sites every day."
Wish one could get reliable statistics in this quick and inexpensive way, but alas, it is impossible. What made the web sites select themselves? How do they distribute over the world? Where does Statmarket keep the pages in foreign languages that would enable a majority of the world's webmasters to effortlessly download and install Hitbox? In what way do the self selected sites differ from all those who did not select themselves. Are their demographics different in some way? They won't tell, but you can be fairly sure that that US servers are overrepresented 10 times or more and non-US servers underrepresented to the point where they constitute a small fraction only. Same as with WebSnapshot.