Hi Andrew
You received that email because you sent me an email.. I use a "challenged response" spam system to protect wife an I from hundreds of Spam messages..
Basically it is a systems that, when it receives a possible spam E-mail from somebody that I have never corresponded with before, it holds the mail and e-mails back a "challenge" to confirm that the person is a real sender and not a mailing robot, in particular a spammer. If it is a genuine person, then when they receive the challenge they respond to it by clicking on the link in the email. The system then releases the mail that was held, and from then on they can mail without challenge.
Hope that makes sens.
Cheers
Michael