Re: Last Call: SMTP Service Extension for Content Negotiation to Proposed Standard

> If the sender is concerned about optimizing for each recipient, they can
> get that effect by reducing to a single RCPT-TO per DATA.

if several recipients have similar capabliities, sending a separate
copy of each message hardly seems like an optimization.

> So it is not as pretty as the separate command, but it permits roughly the
> same mode of operation.

overloading RCPT is simply unacceptable.  It would be a Bad Idea for
any SMTP extension, but this proposal pre-empts RCPT error reporting 
for a very specific application.

Keith