A CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot. For example, humans can read distorted text, but current computer programs can't.
The term CAPTCHA (for Completely Automated Public Turing Test To Tell Computers and Humans Apart) was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford of Carnegie Mellon University. At the time, they developed the first CAPTCHA to be used by Yahoo.
On a couple of occasions, our web server has had a hiccup that prevented the forum's built-in captcha system from working. Rather than continuing the process of working with support and digging around the script code, we're now using a plug-in that offloads that work to a free service hosted by Carnegie Mellon University.
Works great. Check it out by logging out and the clicking "Register"
