The Captcha function is very hard to use. It is very hard for an authorized person to read. This makes it very annoying to the user.
Many internet forums inflict Captcha on it’s readers once when they register. This forum abuses it members repeatedly by requiring it’s use on every post they make.
It is also completely unnecessary. It serves no useful purpose.
The only admirable thing about Captcha is the remarkable sales job they have done on websites, convincing them to purchase this worthless and annoying software. That is case study Harvard Business School might be interested in studying someday.