I also block undesidered banners with it! Unfortunately, you can't block shockwave banners, and images that are in a subspace of the same web site you are viewing. I hope that it will be possible to filter shokwave's, and to filter banners by URL and not only by web site (e.g.: have http://this.site/banners blocked but all other images from http://this.site/ displayed).
The very nature of Perl to be like natural language--inconsistant and full of dwim and special cases--makes it impossible to know it all without simply memorizing the documentation (which is not complete or totally correct anyway).
--John M. Dlugosz