Excellent, but ... Rated 4 out of 5 stars

Excellent, but a small bug, at least on Thunderbird 2 beta2: It only works if the thread pane (the page showing the list of messages in that folder) is highlighted. If the folder pane or message pane are highlighted, pressing Alt+Q does nothing. Having to switch to the message pane is a blow to efficiency, which is what this extension is all about. Otherwise, it's perfect: Quick, simple, and well designed.