Hi,
We've been discussing mailing lists over on the ietf-dkim mailing list, and the issue of when a receiving MTA should trust mail from a list.
I had an idea, though it's only vaguely formed:
It would be nice if a list server would verify subscription requests using OAuth, Windows Live ID Delegated Authentication, or similar. Perhaps instead of the usual verification by email. If <http://fingerprintapp.com/email-client-stats> is accurate, that's about 35% of email users with Gmail, Yahoo, and Hotmail.
If that happened, then then the subscriber's mail system has a chance of understanding that the subscriber has, indeed, subscribed to the list. At that point, the receiving mail system might whitelist mail from that list, provided that it had a good DKIM signature, or an SPF pass, perhaps.
One might even build some sort of federated list management infrastructure, so a user could go to one site to manage all their Mailman3 mailing list subscriptions. With some kind of future standard, perhaps other MLMs could join the party later.
-- Ian Eiloart IT Services, University of Sussex 01273-873148 x3148 For new support requests, see http://www.sussex.ac.uk/its/help/