What does this mean? It means that every web request made by the browser will include a piece of information in the header of the request to tell the web server not to track the web user (more Do Not Track info.) If this do not track feature is enabled, a user has opted out of tracking by sites they do not visit such as analytic tools, advertising networks, and social platforms.
Currently it is up to the web server to abide to the “Do No Track” header. Most privacy conscious web platforms will respect the “Do Not Track” header.
For the user, this means improved privacy. For marketers and web-site owners, this means the analytics, tracking and attribution of conversions from web advertising may get a little murkier, but not completely impossible (see: http://donottrack.us/cookbook/). While this is great news for the privacy concerned public, it makes analytics a bit more difficult for marketers.
This is the first time a do not track option is turned on by default. Firefox and Chrome both have this feature built in, but it is off by default. To see if your browser has “Do Not Track” enabled go to: http://www.mozilla.org/en-US/dnt/.
More on the DNT option in Windows 8 here.