I got a weird email via the contact form on an inactive forum today: He didn't try to register or post any links, so I searched for his email address and discovered he's been doing the same thing on tons of sites, using randomly generated email addresses from dangerbase.com but just sending messages like "Cool site." I took a look at the referring page http://209.235.13.189:444/EFWF/show_queue/ and it was some kind of Django login. Weird; wonder what that was all about.
Probably a spammer testing his scripts out or something. I've had similar random-looking contact form submissions and have always wondered but never been able to actually trace it well. So well done for doing that! I suppose while its doing no harm you're fine. But if it by-passing your spam prevention I'd perhaps consider changing it a bit maybe and see if you get more?