This plugin exists because so many of my regular commentators have been flagged as spammers by Akismet that I stopped using it and started testing alternatives.
Bad Behavior acted very badly - locking four Admins out of my GrowMap blog and requiring the efforts of three of the best WordPress experts to remove.
In the first 48 hours of using a Captcha I had complaints from three regular commentators that it kept telling them they entered it wrong when they hadn't. While clearing their cookies probably would have resolved that our blog readers do not know that!
Andy Bailey, who created the blogger favorite plugin CommentLuv wrote this custom anti-spam solution based on an idea from Phil Hollows of FeedBlitz and improved upon based on input from Dazzlin Donna Fontenot.
My thanks to you all. Now when I log into the blogs I manage - and I am using this plugin in over a dozen of them - instead of a sinking feeling I am overjoyed to only see 12-50 real comments instead of 1,000 spambot generated spammy junk that had to be manually reviewed to find the real comments buried among them.
Before this plugin was placed in the WordPress repository I sent it to dozens of leading bloggers. They will be coming by to let everyone know how it works for them.
We have used it in WordPress versions 3.0.1 down to 2.9.1 with no problems at all. I promised Andy that if he would write the plugin I would provide support so please contact me for support or if you have any questions. I am happy to assist.