You can disable cookies in your browser’s preferences. In the Firefox 3.0 preferences dialog, for example, you can click the Privacy tab and uncheck Accept cookies from sites. Or uncheck only Accept third-party cookies if you don’t mind receiving cookies from sites you navigate to directly. Other browsers provide similar preference options, although the steps to change them can vary.
You can also leave cookies enabled overall, and specifically opt out of DART ad and search cookies. This places a generic DART opt-out cookie in your cookies folder. Advertisements will still be displayed, but they might not be as relevant to your interests.
Update: 22 March 2009