CAPTCHA : Completely Automated Public Turing test to tell Computers and Humans Apart
It is a program that protect websites from bots.
Captcha Applications :
- Preventing Comment Spam in Blogs
- Protecting Website Registration
- Search Engine Bots
- Worms and Spam
Google has developed a reCAPTCHA and calling it :"NO CAPTCHA reCAPTCHA" .
It is easy to use and uses an advanced risk analysis engine and adaptive CAPTCHAs to keep automated software from engaging in abusive activities on your site.
"NO CAPTCHA reCAPTCHA" allows valid users pass through with ease.
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