Review for ImportExportTools by Draconis
Rated 5 out of 5 stars
I stumbled upon ImportExport Tools sometime last year (2010) and have found it to be very useful. I especially like the ability to save email messages in different formats. The add-on has many other useful features as well.
This review is for a previous version of the add-on (2.6.2).To create your own collections, you must have a Mozilla Add-ons account.