if something like DKIM is successful, I would expect an equilibrium
where filters are set extremely high and nearly all good senders
authenticate their messages because otherwise they stand an
unacceptably high chance of having them rejected.
That seems plausible at some point, maybe five years or more from now,
if DKIM catches on and something doesn't blindside us from left field
in the meantime.
Does anyone consider it to be a problem?
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