At 18:09 -0700 on 07/02/2002, Dave Crocker wrote about Re: Last Call: SMTP Service Extension for Content Negot: > > If, on the other >>hand, messages tailored for a each recipient is going to be the norm, then >>VRFY is the correct approach. > > >If the sender is concerned about optimizing for each recipient, they can >get that effect by reducing to a single RCPT-TO per DATA. > >So it is not as pretty as the separate command, but it permits roughly the >same mode of operation. This "one address per copy" approach insures that there will ALMOST ALWAYS be wasted processing and message uploading in any situation where knowing the capabilities prior to message transmission would have allowed the piggybacking of additional addresses onto a copy of the message (IOW: 5 message versions going to a total of 25 addresses instead of 25 copies each addressed to one of the 25 addresses saving thus saving 20 message transmissions). You need to decide what the trade-offs are between minimal number of separate copies (with its processing overhead) and the one message copy per address (with its wasting of bandwidth and throttling of delivery speed due to queuing of messages that could have been passed to the server as part of a prior transmission).