note the disclaimer:

Disclaimers

Traffic data is based on the Internet browsing behavior of WebSearch Toolbar users, which may not be a representative sample of the global Internet population.

Known biases include (but are likely not limited to) the following:

The WebSearch Toolbar works only with the Internet Explorer browser.

Sites frequented mainly by users of other browsers will be undercounted. For example, the AOL/Netscape browser is not supported, which means that we collects little data from AOL users, and our traffic to aol.com is likely lower than it would be for a more representative sample.

The WebSearch Toolbar works only on Windows operating systems. Although a large majority of the Internet population currently uses Windows, traffic to any sites which are disproportionately visited by users of other operating systems will be undercounted.

In some cases traffic data may also be adversely affected by our "site" definitions. With tens of millions of hosts on the Internet, our automated procedures for determining which hosts are serving the "same" content may be incorrect and/or out-of-date. Similarly, the determinations of domains and home pages may not always be accurate. When these determinations change (as they do periodically), there may be sudden artificial changes in our traffic rankings for some sites as a consequence.

The WebSearch Toolbar turns itself off on secure pages (https:) for privacy/security reasons. Sites with more secure page views will be under-represented in our traffic stats