Doubts Cast on Scope of Missing Cookies

NEW YORK A new research report is calling into question polls that showed many Web users habitually delete Internet-tracking cookies.

AQuantive’s Atlas Institute research unit found a significant gap between users’ self-reported cookie deletions and the actual cookie lifespan on their computers. Like surveys done by Jupiter Research and Nielsen//NetRatings, Atlas found 43 percent of respondents said they deleted cookies weekly. Instead of an average cookie lifespan of seven days, however, it was 45 days for those users. Similarly, the 14 percent who said they erased cookies monthly had cookies lasting an average of 59 days, rather than 30 days.

“While surveys can often identify trends, they don’t always correctly quantify the size and rate of the changes,” wrote Young-Bean Song, director of analytics at aQuantive, in the report. “Simply put, what people say and what they do is often not the same.”

AQuantive’s Avenue A, Atlas and Drive PM units rely on cookies to track and target Internet advertising campaigns. It did not report the size of its sample or its methodology.

Jupiter Research last month brought up the specter of widespread deletion of cookies, which are used throughout online advertising to collect anonymous information about Web surfers to track who has seen ads, how often they visit Web sites and what they have purchased. According to a Jupiter survey of 2,300 Web users, 39 percent of users said they deleted their cookies monthly or more frequently, bringing into question the accuracy of Web measurement.

Eric Peterson, a Jupiter Research analyst, said the fact that aQuantive was addressing the issue was positive, since technology vendors have greater insight into the scope of the problem. “Nobody’s saying cookie deletion isn’t happening,” he said.

Atlas downplayed the effect that anti-spyware programs are having on Internet cookies. Popular spyware-removal software lump tracking cookies with spyware programs tabbed for removal. In fact, some programs run paid search ads tied to searches for aQuantive’s own Avenue A and Atlas DMT units. Despite concerns expressed that users would delete third-party cookies as potential spyware, the Atlas study found little difference in the number of short-term cookies encountered compared to six months ago, leading it to conclude users are not deleting cookies more frequently.

Song concluded that cookies remain a valuable and effective gauge of Internet behavior, particular for tracking customer conversions, since between 70 percent and 90 percent occur within 24 hours of a click or impression.