
CAPTCHA images are wonderful. I mean, well, not exactly. I guess, the simple fact that they make spam less horrible is what makes them so great. In a perfect world...there'd be no need. But it's done us a great service. But we shouldn't forget the disservice of the spammers. Every day people across the world spend 150,000 hours typing in CAPTCHA codes. In watts of computer time, that's around 9 megawatt hours a day. Not an insignificant amount!
Which is why Luis von Ahn, who pioneered the use of CAPTCHA with Yahoo!, has created a system to put those CAPTCHA codes to good use. Instead of just a random string of characters, von Ahn has created a system that pulls unreadable words from book digitization projects and uses them for CAPTCHA.

About 8% of words scanned from old books can't be directly digitized by optical character recognition software. So these words have to be filled in manually, an extremely time consuming process. But using von Ahn's new system the words difficult-to-read words get filled in by enterprising commenters and bulliten board posters.
Already the project, called "reCAPTCHA" has digitized over 2 million unrecognizable words through CAPTCHA inputs. Check out recaptcha.net for more information. It's a brilliant idea...thwarting spammers while aiding the infinitely admirable act of digitizing old books. Fantastic!
Via Technology Review


