On Mon, 20 Oct 2003, Dave Crocker wrote:
Rules such as "send mass mail as one copy per addressee" have
significant effects. Not the least, it causes one to wonder why we
bothered creating SMTP, since it's original purpose was to permit
carriage of multiple addressees.
Yes but this rule is a practical requirement. It is impossible to
manage mailing lists on any significant scale without ensuring that a
returned message can be matched to its subscribed email address.
DSNs could work if sites would properly distinguish between
final-recipient and original-recipient. Far too many get this wrong for
this to be a practical alternative at this time.
VERPs are the mechanism of choice, which requires one message per
addressee. Even so, on large lists (over 100,000 subscribers) I find
that as many as 10 returns or so still manage to mangle the failed mail
message in such a way that it can not be automatically processed. I'm
awe-struck by what people get wrong sometimes....
I will further point out that VERPs are an absolute requirement for my
business these days. For example, my servers are on AOL's whitelist for
receiving messages. One of the requirements for being on that whitelist
is receiving notices from them whenever a user clicks the "DO NOT WANT
THIS" button. I am required to remove such subscribers (without
contacting them) when I receive these notices. Failing to do so is
tantamount to getting blacklisted.
The notice you get includes the message that was sent but has the
identity of the user masked, almost. What it doesn't mask is addresses
in Received lines. So, the only way for me to remove the subscriber is
to ensure the destination address is in a Received line inserted by my
server. Keep in mind that people often forward messages to their AOL
mailbox, so getting the notice from AOL is not as helpful as you might
And before you comment on the efficacy of such a system AOL knows
exactly what they are doing, i.e., they have consciously chosen to do
things this way. They don't care whether it's SPAM or not and they are
not the least bit interested in educating users to simply unsubscribe,
even when the unsubscribe link is right there. You can forget about
changing them. They do not care.
And AOL is not alone in thinking this way, they're just the biggest and
leading the way.
Finally, it's not possible to have "one-click unsubscribe" at the bottom of
a message unless you send one message per addressee.
So, one message per address is a requirement for my business.