Most modern browsers include a “Private Browsing” mode that is designed to hide a person’s actions as they browse the web. A new patent filed by Microsoft would make the company’s Edge browser automatically go into private browsing mode on adult sites—though the feature may not provide users with the privacy they expect.

Is Private Browsing Really Private?

Browsers like Google Chrome, Mozilla’s Firefox, Microsoft Edge and Apple’s Safari offer users the option to enter a “private” browsing mode. It’s a popular feature for those who don’t want their search history saved and has been used by 46 percent of Americans, according to a survey conducted by search engine DuckDuckGo.

The top reason for using private browsing, according to respondents to the DuckDuckGo survey, is to hide “embarrassing searches.” Effectively, people open up a private window in hopes of disguising any activity that they wouldn’t want someone to find—a reasonable expectation given the name of the feature.

However, there has often been confusion about just what “private browsing” really provides. According to the same survey, more than 40 percent of people believe using a private browsing window keeps websites, advertisers and third parties from tracking activity. One in four believe using private browsing protects their identity, masks their location and hides their IP address.

Unfortunately, none of that is true. Private browsing does not anonymize the user or block any site or advertiser from tracking what they view online. All private browsing does is prevents the browser from saving the search and browsing history from the private browsing session.

That protection is enough to make sure an embarrassing or private search doesn’t pop up when someone else goes to use the device but it won’t stop an advertiser or internet service provider or any other tracker from identifying who the user is based on their IP address, location and other identifiers like browser version and device.

Microsoft Edge’s Private Browsing Patent

While private browsing may not be as private as many people expect it to be—65 percent of respondents in the DuckDuckGo survey said they felt “Surprised”, “Misled,” “Confused” or “Vulnerable” after learning of the limitations of private browsing—a new patent from Microsoft would automatically save users from some potentially embarrassing or compromising situations.

According to the patent, first spotted by Bleeping Computer, Microsoft would maintain a list of questionable websites that would automatically be opened in a private browsing window in order to prevent it from being stored in the user’s browser history.

Microsoft described the types of sites that may be automatically placed in a private browsing mode as those that contain “unsafe subject matter” such as “adult-oriented content, websites that involve personal user information (e.g., personally identifiable information, financial information, health information, educational information, and so forth), websites that involve protected enterprise data, and so forth.”

The patent would give users the ability to configure the automated feature so that it only switches over to private mode when user-defined triggers tell it to. The content viewed in the private window wouldn’t be saved in the browser and would leave no trace on the computer—though like with any private browsing mode, it could be tracked by advertisers, ISPs, websites and others.