Lately, one of the ad servers on a series of sites I regularly visit, has decided to start occasionally taking over those sites while I am using them. Sometimes this ad server will take over other sites that I didn't think had anything to do with that ad server. Typically my foxfilter will stop half the takeovers because it detects a porn term in the potential site being loaded. But other times I am left having to right-click the back button to return to an earlier version of the site I had originally loaded. I installed a pop-up blocker to attempt cutting back on this behaviour because it also claimed to stop pop-unders, but I am also still getting pop-unders from this particular ad server. It actually jams up behaviour of any tab it decides to start trying to take over. How do I stop this? I already have redirects turned off in Firefox, and the associated message often does come up before the hostile takeover takes place. Help?