Keith Moore <moore(_at_)cs(_dot_)utk(_dot_)edu> writes:
These days for many mailing lists, this isn't even feasible - the list
will filter traffic from non-subscribers. The list might or might not
get so much spam that manual approval of the non-subscriber traffic is
feasible. And whether the sender wants a copy of replies depends
heavily on the nature of the list.
Be careful not to focus too much on the public Internet case here. The
number of public mailing lists that I'm on that allow mail from
non-subscribers has been steadily dropping, but the *total* number of
mailing lists that I'm on that allow mail from non-subscribers has been
increasing and I expect will continue to increase.
Mail internal to organizations doesn't have the spam problem, but can use
the same tools.
--
Russ Allbery (rra(_at_)stanford(_dot_)edu)
<http://www.eyrie.org/~eagle/>