Peter Shute writes:
But from the member's perspective they're being asked to change something they've possibly had for many years, for a reason they don't fully understand, and which they may not even believe.
That kind of thing happens to me all the time (I now live in Japan). Nothing new about that.
After all, they can send ok to other recipients, so why not lists?
If they don't want to learn why not, they'll just have to take someone's word for it. They chose Yahoo!, Yahoo! chose to deny them service. Not the list -- if the list changes *nothing* (that it has "possibly had for many years"), most subscribers will not receive any posts from Yahoo! users. What changed? "p=reject", that's all.
And remember, it's not just lists that Yahoo! is screwing with. It's also "on behalf of" services, including some that are more or less entertainment ("to send this image to your friend, enter her email address and yours"), and some that are the lifeblood of real businesses (eg, invoicing services such as QuickBooks Online from Intuit).[1]
The end result might be to simply drive them away, so I'm in favour of getting their postings to the list somehow.
Fine. I'm just saying what *I* am in favor of. Yahoo!'s tech staff has admitted that they're doing this because it serves their purpose and because nobody can stop them, not because they believe it generally improves the quality of life on the Internet. They under- stand that they're degrading service to their own users and many innocent third parties in order to patch up a security breach that they have not been able to explain, maybe because they don't know, and maybe because it would hurt their business to explain.
IMO, friends don't let friends use Yahoo!
YMMV of course.
Footnotes: [1] @Jim P. This is another reason why the word "transactional" has become unpopular on the DMARC list -- Q.B.O. is an easy example of an automated transactional service that "p=reject" interferes with.