Every day tens of millions of "captchas" are solved by humans, using undreds of thousands of man-hours of work. But what if those person hours could be used for something beneficial? They can be. (you may have noticed recaptcha being used on some notable sites)
posted by delmoi on Nov 8, 2007 - 23 comments

A CAPTCHA to weed out certain potential users of the internet.
posted by exogenous on Apr 4, 2007 - 76 comments

breaking CAPTCHAs. In this case the programmers were able to use software they had already designed to analyze images of people.
posted by delmoi on Jan 31, 2005 - 33 comments

CAPTCHA is the Completely Automated Public Turing Test to Tell Computers and Humans Apart. The test promises to keep online polls honest, block search engine bots, and end spam as we know it. The program generates and grades tests that (1) most humans can pass and (2) current computer programs can't pass. For example, humans can read distorted text but current computer programs can't. To see if you're human or not, take a Captcha test yourself here. To read more check out this nytimes article.
posted by josephtate on Dec 10, 2002 - 27 comments