CNET: Revenge of the Pop-Ups

Two months after Microsoft gave most new browsers a pop-up blocker, not a lot has changed. Both before and after, Nielsen/NetRatings reported that pop-ups constituted about one in fifteen online ad impressions. One pop-up purveyor told CNET that he estimated a little more than half of web users are actively using a pop-up blocking technology. But supply stays up, in part due to sites recoding their sites to spawn windows in ways undetectable for the blockers and in part because of adware and uses of rich media advertising.

And with the supply of pop-ups now more limited to these mechanisms, publishers are pumping up the rates. They say that the pop-ups that get through nowadays tend to be more effective, as often they're ads invited in by the user - or at least not actively blocked. Some internet publishers report rate hikes of 10 to 30 percent. Rates for untargeted pop-ups are approaching $7 per thousand, more than double what they cost last year.