September 23, 2009, 8:49 PM — Many major social networking sites are leaking information that allows third party advertising and tracking companies to associate the Web browsing habits of users with a specific person, researchers warn.
That's the conclusion of a study on the leakage of personally identifiable information on social networks done at AT&T Labs and the Worcester Polytechnic Institute.
The findings (PDF document) , which appears to have received scant public attention so far, was presented by the study's two researchers at a conference in Barcelona more than a month ago. Earlier this week, civil liberties group Electronic Frontier Foundation (EFF) referred to the study in a blog post.
The research, by Craig Wills of Worcester Polytechnic and Balachander Krishnamurthy of ATT, presents "some interesting technical details" on how social networking sites are leaking personal data, the EFF blog post said .
"In some cases, the leakage may be unintentional, but in others, there is clever and surreptitious anti-privacy engineering at work," the EFF said.
Wills told Computerworld that he and Krishnamurthy surveyed 12 of the biggest social networks for the study. They discovered that 11 of them were leaking personal identity information to third-parties including data aggregators, which track and aggregate user viewing habits for targeted ad-serving purposes.
What the study shows is that most users on social networking sites are vulnerable to having their identity information from their profiles, associated with tracking cookies used by data aggregators, he said.
The information allows aggregators to relatively easily scoop up personal data from a user's social network page and to track that user's movement's across multiple Web sites across the Internet.
While aggregators have typically claimed that a person's movement on the Internet is tracked just as an anonymous IP address, the information from social networking sites allows them to attach a unique identity to each profile, Wills said.
What is not known, however, is if data aggregators are actually recording any of the personal identity information being relayed to them from social media sites, Wills said.
He said personal identity data or unique identifiers that point to a person's real identity are often relayed by social networking sites to third parties via so-called HTPP referrer headers. HTTP headers basically identity to a Web page the URL of any resources that link to it.