You have to burn an HTML page to DVD and put it in the map drive. It only decodes simple HTML and .jpg images , so no flash, etc. It sounds like a cool idea, but in the end is somewhat of a novelty that looses it's luster after the first time.
From the Nav manual: "With the browser function, you can display information from discs containing HTML files, 3.2 or newer, on the navigation screen. The files can be accessed and viewed, but no input will be allowed using this system."