CAPTCHA defined is a Completely Automated Public Turing test to tell Computers and Humans Apart.
It is a type of question requiring a human response which is used frequently on website forms to ensure that the response is not generated by a computer. The process involves the computer asking a user to complete a simple test which the computer is able to generate and grade. Because other computers are unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human. The question is usually to identify a weather a subject is present in a photo or to type in letteres/numbers from a graphic image as these.
CAPTCHA – Human answer “CVMV”
CAPTCHA – Human answer “FZDS”
CAPTCHA’s are used to prevent automated ‘robots’ from leaving malware, viruses or spam on your website and will greatly reduce your incoming spam emails if you have a contact or other form on your site.