There are various ways to handle your spam problem. There are various spam detection problems, DNS blackhole lists, etc.
The worst way I can think of is letting others deal with your spam problem. When you send these persons an email, automatically a confirmation email comes back. That email explains you need to reply before they will see the message.
The thought behind these systems is that every reply will be read by a human being. A human being that cares enough to reply.
My main problem is that they make the spam problem worse. As they reply to every message, their ‘solution’ also replies to every spam message with a forged From address. I don’t believe I ever saw a spam message with the spammers email address in the From. When a spammer forges your From address, not only do you have to deal with the bounces, but also the mail bombs from the automated systems (such as these) responding to the spam. Some systems (majordomo) I can understand, but these confirmation systems are just stupid.
Automatically replying is bad, what makes it worse is that these systems do not even solve their problems for them. Perhaps they never want to receive their Bugzilla password. Bugmail mustn’t be important as well. I know some of these systems solve this by having a ‘pending’ folder. This allows the person to see the valid email between all the spam. Making the entire purpose of the confirmation system worthless.
For bugmail the bugmaster mailing list actually receives these confirmation messages. To the senders: go look in your pending folder.