In article <20170510133609.61fba76f@subdivisions.wooz.org> you write:
I probably need more convincing that it would actually be used out in the field, ...
Gmail's already implemented it. I'm pretty sure Yahoo is also planning to.
But OTOH, if it's of some utility it doesn't look like it would be difficult in core to support the extra header. We'd need a small bit of REST and db schema/style setting work so that the list itself could be configured for one-click or not, depending on the web u/i being used. (E.g. maybe one-click unsub is supported in Postorius, but other sites might not support it.)
Keep in mind that the list and user info have to be encoded in the existing List-Unsubscribe header, and one-click just adds a fixed List-Unsubscribe-Post header to tell the recipient that it can do a POST for one click. The encoded header makes regular unsub work better too, since it knows what address to remove and needn't ask the user.
R's, John
It would certainly make it easier to deal with grumpy gmail users, since gmail does not provide junk button feedback.
Let's call that the Grumpy 800lb Gorilla principle. :)
Yes indeed.