Review for Extra Folder Columns by Colin Guthrie
Rated 5 out of 5 stars
Great little plugin.
I made a few adjustments to it recently to add support for renaming newsgroups to more friendly names!
http://colin.guthr.ie/2011/08/thunderavian-renaming-thunderbird-newsgroups/
Hope it gets merged into the official package, but in the mean time people can see my change via the above link :)
Hope some people fine it useful.
Col
To create your own collections, you must have a Mozilla Add-ons account.