Popup killers are often website killers. Bandwidth does not grow on trees and popups allow free sites to exist...like this one. But of course if you have been to the main site (easilly accessable at the Home link at the bottom of this page), you would see that popups are there. It helps NB keep this site free for everyone. In fact, popup killers almost killed this site several months ago.
So my attitude...let popups pass, it helps keep a site going. If everyone killed the popups on this site...the emptyness of the 4 days of this site being down is a glimpse of what it would be like to have a dead site.
Now, I agree that some sites overdo the popups. But then again most of those sites give you "free stuff"...if you catch my drift. If you don't like the popups...don't go there!
So it's your choice...allow a few popups or kill a few sites.