Captchas are annoying. Half of the implementations that have you type in something from the image are unreadable for my eyes. I am sorry that I have to use them on my own blog. This one though, makes it very tough.
I had this on my own MT blog back in the day, when the code that would generate the images failed leaving the user with no option at all, other than to stop participating. Die captchas, die!
I still find that my own CommentQ plugin that lets me customize questions works fairly well. Because even Ajaxian is “niche” no one has an automatic attack. The odd ones that get through are the farms where captchas are shown to real people who solve them. I still remember the time where I had a spam comment get through, and then a real comment right after from the exact same IP, name, etc…. the spam farmer answered a real post! :)
Other Frustrating User Experiences