Latest version of Norton Personal Firewall actually STRIPS "advertising" URL's out of the HTML on it's way to the client's browser.
So textlink URL's from certain hosts, or URL's having certain keywords in them just plain DISAPPEAR from your websites.
Plus ANY images whose size match common banner advert sizes (88x31 and 468x60 etc) are blocked.
See http://abw.infopop.cc/6/ubb.x?a=tpc&...9&m=7116081324 for more info.