How the Site Works

The goal of this website is to help users become more aware of what is known about them by third-party sites, which are sites that are often hidden from view as users visit sites around the Internet.

This website works by using a piece of JavaScript code to check if various popular and specific types of websites are included in the browser's history. For example, the script checks to see if the URL like www.cnn.com/ has been previously visited. Browsers maintain history information by default so that previously visited sites can be seen and their link color can be changed from the default when a page containing such a link is shown. It is not possible to list the contents of the history via such a script, but only to query whether or not specific URLs are contained within the history. The existence of such a script has been previously publicized with a similar site being WhatTheInternetKnowsAboutYou.com.

What's unique about this website is that it not only shows you sites that you have visited, but also shows you the list of third-party sites that track your behavior across these visited sites. This tracking is done in order to build up a profile of your Internet activities so that your interests and other demographics can be inferred thus allowing targeted advertisements to be served. This website shows your inferred demographics of age range and gender based on the set of sites you visit. It also shows your location based on the Internet address of your machine.

Why the List of Sites Shown is an Approximation

The set of visited sites shown to you and the set of third-party sites present on these visited sites is intended for awareness and is likely only an approximation for any user. There a number of reasons that it is only an approximation:
  1. The script cannot examine your entire history, but only query for specific sites. Not all websites containing third-party sites are queried by the script.
  2. The set of third-party sites present on a visited site may change over time. The third-parties shown in the results was determined in October 2009.
  3. Third-party sites typically use cookies to track users. If you remove cookie information or block advertisements then the list of third-parties shown will not be accurate for you.
  4. While this script uses browser history to determine some of the sites you visit, third-party tracking sites do not (to our knowledge) use browsing history to track your behavior. If you periodically remove your history then the list of visited sites shown by our script may be smaller than the list of tracked sites.

What Can I Do to Prevent Tracking

Preventing browser history detection is difficult as discussed in http://whattheinternetknowsaboutyou.com/docs/solutions.html

There are some steps you can take to limit, with various degrees of effectiveness, tracking by third-party sites:

  1. Block known third-party tracking content using ad blocking software or extensions. Some content is easily recognizable, but other content is not and in some cases is "hidden" as part of the visited site domain.
  2. Disallow third-party cookies. Again this helps to limit tracking, but some third-party sites also track some activity via cookies of the visited site.
  3. Disallow all cookies. This prevents all tracking via cookies, but unfortunately the availability of cookies is required by some legitimate sites that you visit so you will then have to selectively allow such cookies.

If you have any comments or questions, please contact us at whattheyknow@cs.wpi.edu