This is not a request for help. I simply wanted to know for myself why the Thunderbird add-on for RTM was suddenly disabled without explanation. It turns out that when Mozilla entered rapid development mode of their browser and email client they changed how they handle add-ons from a security perspective. RTM Provider for Thunderbird didn't meet the requirements of this new code review process. Details can be found here:
https://blog.mozilla.com/addons/2011/02/17/sandboxed-add-ons-disabled-next-week/