Trackback and comment spam handler

For a while now trackback and comment spams have been absent from this site. The process, though, is too manual. With a little luck I'll soon get around to patching the Drupal comment and trackback modules to return 404 errors to comments and trackbacks that contain improper contents. I'd be happier doing this at the Apache level, but without the ability for Apache modules to work based on the content of POST requests it won't work.