Rated 4 out of 5 stars

I made a simple change to make this work for "from" sites instead of "to" sites (but not both). For example, I have images.google.com set to "forge" and "normal" for everything else. Now my RefControl only changes the referrer when opening a link from Google Images to another site.

Load \extensions\{455D905A-D37C-4643-A9E2-F6FEFAA0424A}\components\refcontrolComp.js into a text editor and find the onModifyRequest() function. You'll find a 'for' loop "for (var s = oHttpChannel.URI.host; s != ""; s = s.replace(/^.*?(\.|$)/, ""))". Just change oHttpChannel.URI.host to oHttpChannel.referrer.host, save, and restart Firefox. The list of hosts in your RefControl options now apply to the referring (from) site instead of the site being linked to.

If you want to get technical, oHttpChannel.referrer is sometimes null, but it won't hurt anything and you don't need to worry about it.

This review is for a previous version of the add-on (0.8.13).