Seven percent of Internet users account for more than one-third of the traffic at Web sites, calling into question a popular form of audience measurement, a major study to be published on April 16 finds.
ComScore Inc of Reston, Virginia, a leader in measuring consumer behaviour in stores and in online markets, said a survey of 400,000 home computers has determined that audience statistics for many Web sites may be significantly inflated.
The report takes aim at a common method of tracking Web surfing habits using so-called "cookies," the tiny text files inserted on any computer visiting a site that leave a kind of cookie-crumb trail for statisticians and marketers to monitor.
Many companies use cookies to track visits to their sites and challenge independent surveys that rely on observing panels of selected users, comScore notes.
Internet businesses large and small regularly lock horns with measurement firms such as comScore and rival Nielsen over how to count the number of Web visitors. At stake is the surging amount of money advertisers are will to spend online.
Three in ten US Web users (31 percent) cleared their computers of cookie files during the month, meaning that each time those users returned to the same Web site they were likely counted as a new visitor if the site was using cookie-tracking.
While privacy advocates have long advocated that users block or regularly remove cookies from their computers to avoid aggressive tracking of their computer habits, comScore finds that only four percent of users selectively clear cookies.