Problems with automatic (\"answering machine\") mail responders

[lauren at rand-unix.ARPA]

Luckily, that scenario doesn't happen very often, since many (but not all)
of the responders are smart enough to send only one copy of the
message to any single person, regardless of the number of messages
received.  But this doesn't help with large mailing lists.  If you're
addressing 20,000 people, and only 1% have responders turned on... well,
it's still a lot of junk mail.

--Lauren--