Online Metrics: Who Stole the Cookie from the Computer Log?

Marketers have embraced Web marketing in no small part because of its measurability. But a new report from JupiterResearch puts the accuracy of some Web metrics in doubt.

According to the report "Measuring Unique Visitors: Addressing the Dramatic Decline in the Accuracy of Cookie-Based Measurement," last year 58% of computer users deleted "cookies" from their computers. (Cookies are small files deposited by some Websites onto site visitors' computers; these files enable Website operators to personalize the sites when the visitor returns and to track the effectiveness of their online campaigns and site enhancements.) What's more, up to 39% of computer users may be deleting cookies from their primary computer each month.

"Given the number of sites and applications that depend heavily on cookies for accuracy and functionality, the lack of this data represents significant risk for many companies," JupiterResearch analysit Eric Peterson said in a statement. "Because personalization, tracking,and targeting solutions require cookies to identify Web visitors over multiple sessions, the accuracy of these solutions has become highly suspect, especially over longer periods of time."