> no amount of usability in design seems to have cured the epidemic of
> top-posting!! ;-)
>
Much of commercial email depends on being able to reference the thread of a back and forth communication without searching a mbox for every instance of correspondence regarding the thread. So top-posting works well for the users within that commercial environment - a short response, usually to the last message below the post and the complete thread quoted within the message. User time is more important than bandwidth.
Bottom posting and selective quoting are for a much smaller user base. Like this list. And if Thunderbird is designed with this audience in mind it deserves a trial.
My point is that when you consider design, you have to consider the objective. It's generally accepted that the more specific the objective the more effective the product.
Martin