Captcha for humunity

Image based Captcha systems are becoming increasingly difficult to fill out at places like YouTube, or blogger sites. Frequently takes several tries for me to successfully fill them in. I used a simple phrase instead (though comments are shut down at the moment, if you haven't noticed), and false-positive spam comments dropped to zero. I really like Professor von Ahn's system: I wonder if there is a way I could use it here?

A Dog or a Cat? New Tests to Fool Automated Spammers - New York Times
Captchas are the puzzles on many Web sites that present a string of distorted letters and numbers. These are supposed to be easy for people to read and retype, but hard for computer software to figure out.

Most major Internet companies use captchas to keep the automated programs of spammers from infiltrating their sites.

There is only one problem. As online mischief makers design better ways to circumvent or defeat captchas, Web companies are responding by making the puzzles more challenging to solve — even for people.

They are twisting the letters, distorting the backgrounds, adding a confusing kaleidoscope of colors and generally making it difficult for humans.

“They are creating tests that a reasonably healthy adult can’t pass,” said Gordon Weakliem, a programmer and blogger from Denver, who says he failed to correctly discern the captcha code several times last week on the sign-up page for the Windows Live service of Microsoft....

Not everyone feels that the traditional captcha is finished. Luis von Ahn, a professor at Carnegie Mellon and a member of the team that invented captchas, recently unveiled an effort to give them new usefulness. His reCaptcha project ( seeks to block spam while handling the challenge of digitally scanning old books and making them available in Web search engines. When character recognition software fails to decipher a word scanned in a book — when the page is yellowed or the letters are smudged, for example — Mr. von Ahn’s project makes it part of a captcha.

After the mystery word has been verified by several people, it is fed back into the digital copy of the book. “I heard that 60 million captchas are solved every day around the world, which first made me quite happy for myself but then quite sad,” he said. “It takes about 10 seconds to solve a captcha, so that means humanity is wasting thousands of hours solving them. I wanted to do something good for humanity in that time.”

Ahh, apparently there is. Will have to install this when my site gets righted.


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This page contains a single entry by Seth A. published on June 12, 2007 9:23 PM.

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