A CAPTCHA (IPA: /ˈkæptʃə/) is a type of challenge-response test used in computing to ensure that the response is not generated by a computer
Argh.. and they are horrible. The ones many web sites use are hard for me to read. And apparently they are hard for others to read so you get tons of do overs on them. With the do overs.... well couldn't a computer guess that way too?
They seem like a waste of time, and they hurt my eyes. Down with them!