Quick Pitch: NuCaptcha is a first-of-its-kind CAPTCHA technology that uses video to determine if users are human, not bots.
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NuCaptcha's technology substitutes a brief video display of characters for the usual smash or squiggle of letters. It's definitely easier on the human eye, and its creators say it's also much more secure.
Read More:
http://mashable.com/2010/08/06/nucaptcha/