Four Island

Recently, I came upon a web servive entitled reCAPTCHA. reCAPTCHA is a CAPTCHA system. For those who don't know what CAPTCHA is (shame), CAPTCHA is a method of preventing bot spam on your website. A picture is generated with one or two distorted words on it. A user doing whatever it is you want to protect must type in the words (s)he sees to be allowed to submit his/her comment/whatever.

Many CAPTCHAs annoy people. It seems that all they do is obstruct and prolong the time taken to do something. But reCAPTCHA is different.

reCAPTCHA doesn't just help stop comment span on your website. It helps digitize books. reCAPTCHA sees CAPTCHAs as a way of harnessing human power into doing something useful that cannot be done by a bot. This way, you are not only verifying that you are not a bot when you fill out a CAPTCHA, you are also contributing to a cause.

The people at reCAPTCHA have scanned many books and attempted to convert the scanned pictures into words with OCR software. OCR software cannot always get all of the words, so the words that the OCR doesn't understand are send to be used in a reCAPTCHA. reCAPTCHA then generates a picture with one word that is known and another word that isn't known. The reCAPTCHA assumes that if one of the words are correct, the other one should be as well.

reCAPTCHA can be used everywhere. They've exported their API to many platforms and written plugins for many web applications. For some of these and some better explained information, please visit the reCAPTCHA website at http://recaptcha.org.

I would also just like to mention that the website has a page with a demo reCAPTCHA that you can use to digitize books without verifying anything. It's at http://recaptcha.net/learnmore.html and it's really addicting.