Trying to get an edge on your competitors? NetZero offers a solution that reinforces a "business is war" ethos. The services are called "Ad Missile" and "Ad Missile Defense Shield" and can deliver your advertisement in a separate window above your competitor's site.
Of course, with ad rotations you could still end up with a competitor's ad on your site anyway. But, companies that purchase the "Ad Missile Defense Shield" can protect themselves from an "Ad Missile" hit.
NetZero is an ISP that offers free Internet access to over 2 million subscribers in the continental U.S. Instead of paying access fees, the subscribers are continuously offered advertising material in a separate browser window that users' are unable to close. Because NetZero controls the advertising, they can offer the "Ad Missile" services.
You can check out the company's site at http://www.netzero.com for additional information about their newest advertising weapon. Like the old saying says, "All's fair in love and war!"