When version 10 of Internet Explorer is published, it will default to sending the "Do-not-track" header (DNT). DNT will be enabled in the "Express Settings" Windows setup process. But there will be a "Customize" option that will allow users to stop the DNT header being sent. Microsoft's Chief Privacy Officer Brendon Lynch says that this is consistent with Microsoft's approach to customer privacy and underscores that it is a top priority for the company.

DNT is an initiative promoted by Mozilla and Google that is designed around sending an HTTP header to web sites informing them that the user does not wish to be tracked by the site's operators. It relies on the cooperation of the web site operators to work. Microsoft had promoted its own "Tracking lists" proposal, which is based around preventing the logging of user behavior.

The W3C has been overseeing the standardization of DNT. To date, it has required that browsers only send the DNT header when the user has explicitly requested it in the settings. Microsoft's decision to deviate from this rule has met with criticism from supporters of DNT. They fear that if the header is set by default, it could lead to a loss of acceptance among advertisers and, without their support, lead to the failure of DNT. The W3C recently called for compromise around the DNT standard. The European Commission has expressed PDF support for Microsoft's position.

Sites use many different methods to investigate user behavior and these different methods are typically grouped under the single term "tracking". The goal is usually to sell advertising by matching the user and site with an appropriate advertisement. DNT and tracking lists should allow the user to browse without being logged.