> Ad networks insist on this because there's no other way to prevent massive-scale fraud by the customers - how should the ad network know that the end user is

> Ad networks insist on this because there's no other way to prevent massive-scale fraud by the customers - how should the ad network know that the end user is a "real" user and not a fake request the customer generated to drive up the impressions on pay-per-impression ads? Then get rid of pay-per-impression. I'd rather have the days of affiliate links than the crap we have now. You advertise a widget on your site, I click on it and buy it. You get a (small) cut of the profit. It also tends to make ads match site content, since I won't be buying left-handed spanners advertised on a site dedicated to short-haired pomeranians, probably.