CAPTCHA

Wikipedia
CAPTCHA = Completely Automated Public Turing test to Tell Computers and Humans Apart
http://en.wikipedia.org/wiki/Captcha

CAPTCHA Project
The CAPTCHA Project is a project of the School of Computer Science at Carnegie Mellon University. It is funded by the NSF Aladdin Center.
CAPTCHA is a trademark of Carnegie Mellon University.
http://www.captcha.net/