> I've never heard of an E-mail client that supports automating this, and
> I'm not entirely sure I'd want it automated, although a "did you forget
> to finish this?" reminder such as my Thunderbird configuration provides
> when I type a word like "attach" but don't include an attachment might
> be helpful.
FWIW, Emacs does offer support for that kind of footnotes, of course ;-)
Stefan