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What A Website Knows About You


All the cool web sites you visit need to know the properties of your “user agent” (in today’s environment it is your web browser) in order to optimize the views and transactions of the pages you visit on your device. This information (browser and version, operating system and version, etc.) is provided to the web site in the user agent header field. This information is important to the web site application developers in order to enhance the end user experience — but like a lot of conveniences, this type of information about your system can be a privacy concern.

As it turns out, your browser and associated add-ons can provide a lot of information to the web site that wants to request and use it. Here are some of the data that can be acquired during your visit to a web site:

  • Browser & version
  • Operating system and version
  • Device manufacturer and model of your device
  • Screen resolution
  • System fonts
  • Current viewport (size of the useful browser window)
  • Color depth (bits per pixel)
  • JavaScript, Java, Flash, Silverlight, etc (available)
  • Cookies (available)
  • Super cookies (available)
  • IP Address
  • Geo-location (latitude, longitude)
  • Language (language identification code)
  • Time zone
  • Facebook, Twitter, Google+, Google login status
  • Ad blockers (active)
  • Connection speed (measured on the server)
  • MAC address (physical network device address)
  • Plugins (a list of installed plugins)
  • Proxy (is a proxy being used?)

Because mobile device browsers have far fewer capabilities than desktop versions and because the mobile device manufacturers learned about of the security and privacy problems that desktop systems suffered, there is less information available to sites about mobile systems. But that does not stop a lot of the stakeholders from trying to traffic your visits (see UHID notes below).

If you would like to see what data your system is potentially exposing to sites, you can visit BrowserSpy or the Electronic Frontier Foundation’s Panopticlick website.

It is pretty clear that if you combine information such as IP address, geo-location, device model, language code, time zone and MAC address, that web sites can readily identify your device uniquely. This is called a digital fingerprint and we will discuss this further in the article.

Editors Note :  We DON NOT save any info from our users


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