After I switched from Movable Type to WordPress as my blogging software, the comment spam problem has returned from the grave. So I’ve looked for good solutions for WordPress: I ended on a verbal CAPTCHA with a math question (which may also keep stupid commenters out – not that I have any of those, of course). I am considering some of the “fight-back” solutions out there too: Maybe returning a really big response really slowly when spam is detected, like Spammer Tar Pit.
If you have any experience or thoughts on the subject (or if my CAPTCHA is broken), please let me know.