BERKELEY, Calif. - Web users are tracked far more widely than they know, University of California at Berkeley researchers revealed this week.

Companies often provide information about people who visit their Web sites to others, despite assertions to the contrary, the study concluded. Some tracking software collects detailed information on how people use the Internet.

"Some third party will then know that a computer from your (location) visited a Web page, and they'll know the content of the page you viewed," said Ashkan Soltani, one of three UC Berkeley graduate students who compiled the study as part of their master's project before graduating last week.

"There's no transparency about how that information is used," he said.

Although it has long been known that companies track Web users, researchers were surprised by how ubiquitous the practice is and how few sites mention the practice in their privacy policies.

Popular blogging sites were among the most active trackers, the students found. Blogspot, for example, had 100 "bugs" - or tracking beacons - on its site, while Typepad had 75.

Despite privacy policies that assure users that companies do not collect personal information on their Web sites, many find loopholes that allow them to do just that, said Brian Carver, a professor at the UC Berkeley School of Information who advised the students.

"They may not be sharing the information themselves, but they're inviting other companies onto their sites to collect the information," he said.

The study also found Google-related trackers on 88 percent of the nearly 394,000 bug-equipped domains examined by researchers.

"Google's sheer dominance of the tracking market surprised us," Carver said.

Google representatives did not return a phone message Wednesday.

The Federal Trade Commission is investigating the Internet giant's tracking practices at the behest of the Electronic Privacy Information Center, said Marc Rotenberg, executive director of the Washington, D.C.-based organization. FTC representatives declined to comment Wednesday.

"Google is in a better position than any other company to control Internet activity," Rotenberg said. "It simply has more information than any other company."

Although computer users can buy or download software to protect them against more malicious tracking programs that steal personal information such as credit card numbers, defending against Web bugs is significantly more difficult, researchers said. The few tools that do exist can make it nearly impossible to surf the Web.

"Even for the advanced user," Carver said, "it can make browsing the Web extremely frustrating."

(c) 2009, Contra Costa Times (Walnut Creek, Calif.).

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