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Being able to access porn on the internet might be convenient, but according to researchers it's not without its security risks. And they're not just talking about viruses.

Researchers at Microsoft, Carnegie Mellon University and the University of Pennsylvania analyzed 22,484 porn sites and found that 93% leak user data to a third party. Normally, for extra protection when surfing the web, a user might turn to incognito mode. But, the researchers said, incognito mode only ensures that your browsing history is not stored on your computer.

According to a study released Monday, Google was the No. 1 third-party company. The research found that Google, or one of its subsidiaries like the advertising platform DoubleClick, had trackers on 74% of the pornography sites examined. Facebook had trackers on 10% of the sites.

"In the US, many advertising and video hosting platforms forbid 'adult' content. For example, Google's YouTube is the largest video host in the world, but does not allow pornography," the researchers wrote. "However, Google has no policies forbidding websites from using their code hosting (Google APIs) or audience measurement tools (Google Analytics). Thus, Google refuses to host porn, but has no limits on observing the porn consumption of users, often without their knowledge."

Google didn't immediately respond to requests for comment.

"We don't want adult websites using our business tools since that type of content is a violation of our Community Standards. When we learn that these types of sites or apps use our tools, we enforce against them," Facebook spokesperson Joe Osborne said in an email Thursday.

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Elena Maris, a Microsoft researcher who worked on the study, told The New York Times the "fact that the mechanism for adult site tracking" is so similar to online retail should be "a huge red flag."

"This isn't picking out a sweater and seeing it follow you across the web," Maris said. "This is so much more specific and deeply personal."

Originally published July 18, 8:55 a.m. PT.

Update, 11:55 a.m. PT: Updated with response from Facebook.

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