I don't agree, I think there is something more to this. I get the pop-ups on hornfans and drudgereport only. It happens when you click on a link on the page and it only happens once during the visit...usually on one of the first links you click on. I'm always sweeping for adware and spyware. I think the trigger is coded into the webpage.
Not spyware. I use firefox and have all unrequested pop-ups blocked, but once a day on hornfans a pop-up gets through. It happens when I access the site from my linux system as well which seems to rule out spyware. I think somehow the flash banner ads are responsible.
Hmmm. I don't see pop-ups, but I use Mozilla 1.7, not Firefox. I did install a plug-in called Adblock from the Mozilla folks, but I don't know if it's available for (or built in to) Firefox.