What The Internet Knows About You

Martin Brinkmann
Feb 17, 2010
Updated • Jul 3, 2016

Most Internet users know that a website they visit can access various information about the computer system used to make the connection.

This includes the screen resolution, operating system, IP address and web browser among other things. But those are not the only information that can be gathered when users visit a website.

What would you say if someone told you that sites can find out additional information about you. Your Facebook or Twitter friends, websites that you have visited in the past including financial, government or adult ones, email accounts or even what you have searched for in the past using search engines.

The What The Internet Knows About You website will display those information and more on its website to all users who are connecting to it.

What The Internet Knows About You

The method the website uses to retrieve and display those information is not a hack or exploit. It uses built-in functionality of all modern web browsers to do that. It basically makes use of the feature to display visited links in a different color than not visited links.

All that needs to be done is to display those links (hidden to the user) on the website and check their link color to find out if a user has visited them. The method checks popular links against the user's web browsing history to see if the page has been visited.

The What The Internet Knows About You website contains general link collections, e.g. the top 5000 or top 20000 websites in the world but also specialized checks for banks, social networking sites or government websites.

The service explains in detail how the information is retrieved and what users can do to protect their privacy so that these information cannot be retrieved.

  • Disabling your browser's history
  • Disabling CSS styling of visited links
  • Using a special browser extension to fix the problem

If you want to find out for yourself visit the project's website to find out what the Internet knows about you..

Update: Please note that the loophole has been fixed by browser makers so that it is no longer working. The website the test was run on is also no longer available as a consequence.

You may want to check out this guide about browser fingerprinting though which reveals what your browser reveals about you to sites you connect to using it.

What The Internet Knows About You
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What The Internet Knows About You
What The Internet Knows About You is a free Internet service that may reveal information about sites you visited in the past.
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  1. GR Terrero said on February 18, 2010 at 11:48 pm

    My comp’s squeaky clean. It found nothing, nada, zip, zilch, nichts, nix, rien, niente!

  2. paulus Bekkers said on February 18, 2010 at 5:23 pm

    Great find Martin i found a few great tips.

  3. Transcontinental said on February 17, 2010 at 6:34 pm

    Are we allowed to know what they know about someone else than ourselves? :)

    Right now, page doesn’t load. Gee, I guess we’re a bunch to wonder what they know that we ignore!

  4. Helix said on February 17, 2010 at 6:02 pm

    http://www.webmii.com is a similar site

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