Works like a dream; Except on Youtube. It still blocks midroll ads like it should, but re-opening youtube tabs after I open Firefox again makes the blocker miss the midroll ads completely. Either reloading the tab or turning the blocker off and on again starts blocking the ads like it should, so it's not completely hopeless. But it's certainly an annoying snag.

thanks

A really reliable add-on for blocking ads, though one must disable if a certain website needs selected scripts to function, but otherwise good.