All the discussion so far about this draft hinges on one question:
Is it necessary for anyone other than the "Final MTA" and "Final Delivery
Agent" to understand the semantics of subaddresses?
Put another way, is there ever a case where a sending agent needs to start
from a primary address, compute a subaddress by some means other than user
input, and direct the message to the concatenation of the two?
If so, then there's a good reason to standardize the format of the primary
and sub-addresses, and to standardize the way they're concatenated.
If there is not, then failure to standardize is only an inconvenience. It
means that a sub-addressing scheme that worked when the user received mail
at domain X may stop working when he moves to domain Y, even if both claim
to support sub-addressing.
Some inconveniences are severe enough to warrant a standard to mitigate
them; I suspect there'll be dissention over whether this is such a case.
At this point I don't find the arguments for standardizing to be strong
enough, though an informational document might be nice. I'm willing to be
convinced otherwise, though, because I do get mail via several domains and
do feel the inconvenience of inconsistent or absent subaddressing schemes.
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com