Firefox backers aim to 'destroy' IE with campaign
 

If a Web site owner chooses "gentle encouragement," visitors to a site who are using IE will see a banner across the top of the page that encourages them to download Firefox. A "semi-serious" site will put up a splash page encouraging a user to download Firefox, with a link for downloading Mozilla's browser as well as a link to the Web site. Those who choose the "dead serious" rating actually block users with IE from viewing the page, informing them they must install Firefox to view the site.