In other words, they're double-dipping.
Ten percent may not seem like much, but the contested 10 million pageviews a day represent more traffic than all but the largest web sites see in a month. By any measure -- even without double-dipping -- Yahoo is still the most popular search service, but the discrepancy casts a shadow over one of the key numbers that led investors to drive Yahoo's stock price up 17 1/4 points Thursday, adding $790 million to the value of the company.
Two years ago the most quoted traffic number was "hits," an inflated server statistic that was mistaken by an underinformed public for the number of human visitors. Now expectations -- not to mention investments -- are even higher. Terms such as "pageview" also need to be clarified, especially now that blue-chip web companies with multibillion-dollar valuations are counting 10 million of them twice every day.