An odd, and somewhat nasty, thought... So far, the two organizations (at least of which I'm aware) that have made more or less public announcements of their intentions to use the sort of restrictive policies that cause mailing list problems are not only large providers of email but also large providers of online forums, social group discussions, etc. So are several of the other member-contributor organizations to dmarc.org. As far as can be observed from the outside, those forums and discussion groups make considerable contributions to the bottom lines of those providers -- in most cases, they allow those organizations to sell advertising and/or to sell their users and their interest profiles to advertisers. Email, by contrast, is typically a service they provide in conjunction with those other services but is not, itself, generally a profit center. For many of the users and uses of the extended Internet, mailing lists are the historical predecessor, and sometimes a contemporary alternative, to those forums and centralized "social network" discussions. If one examines those relationships, there is a case to be made that the problems they cause to mailing lists is not "collateral damage" at all. Even if the effects were discovered by accident, continued use of DMARC with restrictive policies has the consequence of driving traffic away from mailing lists, perhaps especially mailing lists operated by smaller providers and non-profits, toward use of the for-profit systems operated by those same (to quote another recent comment) "too big to ignore" operators with a positive effect on their bottom line to the detriment of other operators and ways of doing things. Behaviors by large ("dominant", "too big to ignore", etc.) industry actors that have the effect of driving alternate solutions or providers out by mechanisms other than fair competition in the marketplace, especially when those mechanisms come out of collaborations among such actors, are, if other conditions are met, rather seriously illegal in many countries. If intent can be demonstrated, they are even more so. So, as a purely hypothetical set of questions (I am not recommending anything), I wonder what would happen if some of the people who have been claiming they or the general public are harmed by this would, instead of asking what the IETF can do about something that is not an IETF Standard, went to their local "competitiveness" or "antitrust" authorities, explained the situation and started complaining? I also wonder whether the IETF and ISOC have, or should seek, legal advice about how to keep adequate distance between themselves and this situation should some relevant jurisdiction initiate an investigation or enforcement action. Just curious. john