On second thought, Y Groups also allow replying from your mail client, so that's where the issue is I believe.
--- In korgpolyex@yahoogroups.com, ASSI <Stromeko@...> wrote:
> As a matter of fact, I already did that years ago. Bill's mails are the
> only ones I get as HTML and he did send two or three inbetween as plain
> text, so I think the configuration error is at his end (he seems to send in
> HTML _only_ most of the time).