Traditional CAPTCHAs are often hard to solve and therefore Facebook is experimenting with social authentication where theyâ€™ll show you a few pictures of your friends and ask you to name the person in those photos.
Dr Luis von Ahn invented CAPTCHA images that websites ask you to type to post a comment or send an email.
The next time you download a file from RapidShare, you may be asked to solve a tough CAPTCHA image.
The most interesting and hard to break CAPTCHA image so far..
Amit Agarwal is a web geek and founder of Digital Inspiration, a popular tech & how-to website since 2004 ..read more