Getting tons of comments spam at the mo. Rogi clued me into this solution and I'm in the process of coming up with some variations on the theme.

Please excuse any building dust.

(Update: because I can't deal with going through every entry and marking the comments as closed, I've taken the comment form off the individual archives. This means that the only place people can comment is in the pop-up comments boxes. At least for now. I'm going to have to have a think...)