Rated 5 out of 5 stars

A good alternative is Leechblock, as this plugin has not been working on my setup: OS X 10.5.8 and Firefox 3.58.

Here is the link: https://addons.mozilla.org/en-US/firefox/addon/4476

3 Stars for the good intention of this PlugIn though... :-)

This review is for a previous version of the add-on (0.7.1).