Murray asked a couple of interesting questions, which I will address
separately in separate message threads.
To the question why are mailing lists special, they're somewhat special,
but they're more interesting here as canaries in the coal mine.
As a rough estimate, roughly 90% of e-mail is spam, most of what's left is
bulk broadcast mail, most of what's left after that is transactional
sort-of-broadcast mail, and the little bit at the end is discussion lists,
individual mail, and some miscellaneous other stuff. Nonetheless, people
have consistently said that they want to get their individual mail, and
don't care about the broadcast mail. I'm not aware of surveys where they
ask specifically about discussion lists, but since each message is
generally hand written by an identifiable person, I'd expect people to
consider it a lot closer to individual mail than the daily blast from
BigCo.
So mailing list mail is special for the same reason individual mail is
special--it's the mail people want.
The reason it's not special is that it's just the most visible example of
a wide variety of legitimate useful mail that DMARC can't describe, and
that are broken by DMARC policies other than p=none.
For example, I send and receive my Yahoo mail on my Gmail account, and
have done so for years. Gmail makes the obvious checks to ensure that
it's my account, so it's just as secure as sending from Yahoo, and it's
useful. Or it was useful until last weekend. Now a lot of it bounces.
Or there's the WSJ's mail an article feature. It's useful, nobody abuses
it. Yahoo users can't use it any more.
There's lots of these, and the only thing "wrong" with them is that DMARC
can't distinguish them from other somewhat similar mail sources that send
spam. The proposals I'm seeing from the DMARC cartel are basically Google
Purge applied to e-mail:
http://www.theonion.com/articles/google-announces-plan-to-destroy-all-information-i,1783/
Surely we can do better than that, but that's the next message.
Regards,
John Levine, johnl@xxxxxxxxx, Taughannock Networks, Trumansburg NY
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