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Wednesday, March 25, 2009

Daniel Brandt on Google/ DoubleClick Tracking

Google-critic Daniel Brandt at writes:

This week Google began recording the web surfing behavior of everyone who visits any page that uses AdSense or DoubleClick. It happens as soon as the page loads – no clicking is required. Their new cookie has a unique ID and is similar to the same sophisticated system that was developed over the last ten years for the cookie.

Many major sites use AdSense. It took me a minute to find AdSense on,,, and, and then I stopped looking because my suspicions were already confirmed. Even apart from AdSense, DoubleClick ads are all over the web. Unless you disable JavaScript, which makes surfing inconvenient on many sites and impossible on some, you are getting thoroughly tracked.

This tracking is a major move on Google’s part. The referral from the phone-home to contains the complete URL of the page you are viewing. It happens in the same instant that your browser offers up the unique ID from your cookie. Google can add a time stamp and your IP address – and knowing Google, they will.

While Google says that it is dicing this information so that it can merely stick you into a number of broad interest categories, we have to assume that Google is saving all of the information they collect. It would not make sense to identify the relevant categories on the fly and then throw away the details. That would preclude future development into a more finely-grained system. Yes, we have to assume that Google saves everything, until such time that Google allows auditors into the Googleplex and the auditors say otherwise.


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