Essential Add-on Rated 5 out of 5 stars

I can't imagine browsing without this now.

This review is for a previous version of the add-on (3.1.2.1-signed). 

Firefox yes, Thunderbird no Rated 4 out of 5 stars

This add-on works great in Firefox, including Cool Previews windows. It Does Not Work in Thunderbird 3.1, however. They should make this more clear, or better yet, make it work.

This review is for a previous version of the add-on (2.7.6.1-signed).