Have you ever filled in a web registration form on websites like Yahoo! and Google where you have to type in some text from an image of some distorted characters or words?
This is a security measure called CAPTCHA. A CAPTCHA is a program that can tell whether its user is a human or a computer. CAPTCHAs are used on websites to prevent abuse from “bots,” or automated programs usually written to generate masses of annoying spam. Currently computers find it difficult to read distorted text as well as humans can, so this means bots can’t hijack forms protected by …
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