Rated 5 out of 5 stars

This add-on earns 5 Stars, because it works fine with FF 7.0.1 and TB 7.0.1 and higher and it is very usable. I have deleted Extended Copy Menu (fix version) in FF (does not work with any versions of TB) for using Copy Pure Text, because this extension works with both. The developer also should get 5 Stars, because he cares for his add-ons and for the users of his extensions, and he reads the reviews and he reacts.
My commend: T O P.......... thank you very much.

Copy Pure Text works fine with FF 6 (5 Stars), but not with TB 6 (this is the reason for 4 Stars)................ I hope in future Copy Pure Text will be developed for Thunderbird 6 and higher

This review is for a previous version of the add-on (1.0). 

Version 2.0.0 is compatible with thunderbird. Give it a try. For any feedback, feel free to email me.