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.