They really don't, even for large sites. comparison: - http://www.quantcast.com/macrumors.com#traffic http://www.quantcast.com/macrumors.com#traffic (measured

They really don't, even for large sites. comparison: - http://www.quantcast.com/macrumors.com#traffic http://www.quantcast.com/macrumors.com#traffic (measured) - http://siteanalytics.compete.com/macrumors.com/ http://siteanalytics.compete.com/macrumors.com/