Ok and now...

How about all those mail server operators out there having to check the validity of headers before they send out "undeliverable mail" or similar bounce messages?

A couple of months ago someone started forging spam from my business domain and in just one week I received over 4,000 "delivery failure" e-mails.

Not only that, it seems that some legitimate business e-mails I *had* sent had been filtered out by servers which said "hello, we're getting lots of spam from this domain, let's block *all* messages from it" which meant that customers were contacting me to check whether their orders had been received.

Some of the problem with spam is not the spam itself, but the results of that spam :-(