I've actually had a couple of threads on here trying to figure out why I am spamming people. Through the tests I've done, it's not an open relay, at least according to the couple of sites I used to test my server.
The only contact form I have is on my forums. It requires an e-mail address, image verification, and a message. The form sends all mail to firstname.lastname@example.org
. I don't see how they are using that form.