> Mozilla is getting blacklisted for sending to now-nonexistent addresses Not quite, the problem is that the addresses do still exist, but they're inactive and

> Mozilla is getting blacklisted for sending to now-nonexistent addresses Not quite, the problem is that the addresses do still exist, but they're inactive and the mail is never being read. It sounds like some blacklists use "continuing to send mail to known-inactive addresses" as an indicator of a bad sender.