It is very important that autoresponders not reply to certain addresses,
such as <>. Also for most applications they should be rate limited to
something like one message a day.
If the address is potentially on a mailing list (as is the case for most
people's mailboxes), then the program should also try to determine which
messages are list messages and not reply to them. You can do this by checking
the recipient headers for the user's address(es). Checking the precedence
header for bulk or junk. Checking for an envelope sender with a local part
ending in -owner.
It would be nice if there was an rfc for autoresponders out there, as there
seem to be more and more people using braindead ones.
