Just had a look through the comments that had been posted to my essays site and disappointingly, every single one was a spam attempt.

I'll probably have to go back through the web logs and see if there were any more attempts to post, so as to determine if my (rather weak) anti-spam measures actually work.

Some quick looking indicates "no, not at all". The measure I've taken is (essentially) to have a hidden field, initialised to an empty string, with a name that (ideally) should trick a screen scraper to fill it in and simply not file the comment if that is present.