I am trying to figure out if there is an better purposed extension that can block URLs only, since I found a possible problem with my solution.
If you have a filter to block all images from somesite.com, all page views from that domain will also get blocked when turning on Site Blocking. Also, some pages with ad-like words in them may also be blocked (somesite.com/index_ads.html, etc) if you have a large and/or complex set of filters (mine are; from
http://www.geocities.com/pierceive/adblock/).
There's an extension to Multizilla (
LINK) that perhaps will do the trick, but this is not released for Firefox yet.
Anyway, if you don't have too complex filters, you should do fine with this fix I think.
Adde