Web trackers know more about you than you think

Worcester, Mass – Social networking sites are routinely making specific personal information on their users available to tracking sites, according to a report.

The study cites Facebook, MySpace and Twitter as allowing this leakage, and describes just how tracking sites can use the information to link browsing habits to specific individuals.

With a unique identifier, a tracking site could gain access to a user’s name, physical address, email address, gender, birth date, educational and employment information, and much more.

“When you sign up with a social networking site, you are assigned a unique identifier,” says Craig Wills, professor of computer science at Worcester Polytechnic Institute (WPI). “We found that when social networking sites pass information to tracking sites about your activities, they often include this unique identifier. So now a tracking site not only has a profile of your web browsing activities, it can link that profile to the personal information you post on the social networking site. Now your browsing profile is not just of somebody, it is of you.”

Wills says the researchers do not know what, if anything, tracking sites do with the unique identifiers once they’ve got them. He says they’ve asked, but haven’t heard back officially from any.

“We are not saying that they are necessarily trying to leak private information,” he says. “But once someone is in possession of your unique identifier, there is so much they can learn about you. And even if tracking sites do not use the information themselves, can they guarantee that it will never find its way into other hands?”