Today I was forced to add a captcha system to my blog because of the same spammer that has been hitting me for days now. Every 10 minutes I would check and notice 2 or more spam comments filled with links to porn and reported attack sites.
I decided to use the conditional captcha plugin which would deter the spam, and hopefully not get in the way of my normal readers. This plugin works in a way that if Akismet detects a comment as spam and filters it, it would go to captcha. If the person (or bot) failed the captcha, then that comment would be permanently deleted. If the captcha is entered correctly, it would then go to my spam comments area where I can manually approve it.
Regular commentators should never even see the captcha because of how it works. I just cannot let a constant attack go on and still maintain this blog with quality content.