Even if one goes back to the original SMTP specification,
RFC 788, the purpose is "to return non-delivery notices".
right.
But for cases such as a message
sent via a mailing list expander (introduced in RFC 822),
the non-delivery notices would simply be annoying if sent
to the message author,
it was as irritating then, as it is now.
So for early SMTP documents, which didn't consider mailing
lists as we now know them (those documents discuss expansion
nevertheless, mailing list mechanisms, of the same flavor as we have today,
were in operation at the time smtp was written.
d/
--
Dave Crocker
Brandenburg InternetWorking
+1.408.246.8253
dcrocker a t ...
WE'VE MOVED to: www.bbiw.net