Completely
Automated Public Turing
test to tell Computers and Humans
Apart.
CAPTCHA is an image containing a numerical or
alphabetic code that can normally only be read and interpreted by
a human. It is used to verify a form or other log in on a website
to prevent computers from spamming the form. There are various
CAPTCHA systems which can be installed behind a web form as
demonstrated in this dummy form.
Your Name*
Your
Email*
Subject
Demo CAPTCHA
RECAPTCHA
Is a free resource from Google which can protect a domain and is
secure and fairly easy to set up. The user types in the two words
before sending the form.