Most of us have seen them, CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart). Those weird looking characters that we need to re-type in order to gain access to some web site or resource. Well, they serve a purpose and that is to make sure the user is a real live person rather than some computer script trying to hack a site by perhaps trying to flood the server with large numbers of requests.
I just found out about a brilliant service called reCAPTCHA. It is totally free and with a few lines of code you can add this security feature. But what makes it brilliant is that the service is also digitizing books while it is being used. That's right each time a person types in the characters of the CAPTCHA scanned text from a book is being digitized.
How does that work you may ask?
From the reCAPTCHA site
But if a computer can't read such a CAPTCHA, how does the system know the correct answer to the puzzle? Here's how: Each new word that cannot be read correctly by OCR is given to a user in conjunction with another word for which the answer is already known. The user is then asked to read both words. If they solve the one for which the answer is known, the system assumes their answer is correct for the new one. The system then gives the new image to a number of other people to determine, with higher confidence, whether the original answer was correct.
If you working on a site and require CAPTCHA then please check this service out. It's free and better yet your users will be helping out, digitizing books.
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