When we first released our study on private browsing modes, a lot of people were shocked to see that websites could still track them even when they blocked cookies and used private browsing (aka “incognito mode”).

To see for yourself, check out Nothing Private, an example site that showcases private browsing tracking in the real world.


The main method used to uniquely identify and track people while using private browsing is called “browser fingerprinting.” Just as each person has a unique fingerprint, so does every browser. Websites can look at version numbers of your browser, the plugins it uses, and dozens of other points of browser information to create a unique ID, a browser fingerprint, that can then be used to track you.

Want to see some of the more interesting things that can be used in browser fingerprinting? Check out the interactive site ClickClickClick that shows you this information as you interact with it in real time. It’s spooky!

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Disclaimer: This article was originally written by DuckDuckGo.