The Phoenyx has been receiving a lot of spam backscatter (see the Wikipedia explanation: http://en.wikipedia.org/wiki/Backscatter_%28e-mail%29 ) lately, meaning our domain name and sometimes working email addresses have been forged on spams. Generally, there's nothing we can do about this - they're not originating from our server, someone's just sticking our return address on

There is one exception: if you're using a challenge/response system, your challenge is spamming me. I will respond affirmatively to it, ensuring that the original spam (which we didn't send) makes it through to you. Because hey: you're effectively pestering previously-uninvolved strangers to do your spam filtering for you. Challenge/response is just plain a bad idea.