I recently discovered AdBlock Plus Firefox plugin (found here). I rate this as the most useful plugin I have ever used in Firefox. I don't see ads on my pages anymore. Whenever there is something annoying or offensive, I can remove it permanantly. It improves your load speeds because you are not loading flash ads or other unnecessary images. I do not see advertisments when I browse the web anymore because I have blocked all of the major suppliers. It is truely wonderful. I cannot reccommend it enough.