The term “CAPTCHA” was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper (all of Carnegie Mellon University), and John Langford (then of IBM). It is a contrived acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart”, trademarked by Carnegie Mellon University.
A CAPTCHA is sometimes described as a reverse Turing test, because it is administered by a machine and targeted to a human, in contrast to the standard Turing test that is typically administered by a human and targeted to a machine.
Lately on web sites were I have to validate I’m getting captchas like this:
Sometimes I get three or four in a row which are unreadable. Would it just be better to hire a few network police and have public humiliation for anyone caught defrauding a web site with spam? These things are really just another way spammers abuse us.