Captcha
From JumbaWiki
A CAPTCHA is an acronym for "completely automated public Turing test to tell computers and humans apart". It is a method for preventing robots and spammers flooding form pages by getting a human to retype an obscured text that can't easily be recognised by OCR (optical character recognition) software.
External links
- http://www.finalwebsites.com/snippets.php?id=39 sample short snippet you can use on your site (requires GD library)
- http://en.wikipedia.org/wiki/CAPTCHA Wikipedia Captcha article

