I have already tried to get feedback on How to include CAPTCHA support for anti-spam comments?
and a corresponding post of mine in Comment Spam Plugin
, but haven't received a response so far.
But since I was really in need of a better anti-spam solution for anonymous commenters, I hacked the required functionality myself into Geeklog. Maybe I could have written a plugin, but noone gave me a hint how I could include this feature as a plugin (if it is possible at all).
The CAPTCHA anti-spam hack works as follows:
-- Geeklog shows anonymous users a randomly generated image
with a security code, which the anonymous user has to enter correctly; if the user's input (response) does not match the supplied image (challenge), she sees an informative error page and can retry on a newly generated image
-- In my current hack, registered users do not need to enter the security code; it is only targetting anonymous posters
If anyone (or the devs) wants to know more about it, you're welcome to post your questions in this thread.