If you have a blog of your own, you know what a CAPTCHA is; for the rest of you, you’ve probably cursed at more than one. CAPTCHAs are those garbled images of words that you must decipher on many web sites to prove that you’re a human and not an evil spamming robot. If you’re like me, you find them at least mildly annoying. Until now, anyway.

I stumbled across reCAPTCHA over the weekend. Most CAPTCHAs use random words to prove you’re human, but this one shows you images of actual scanned text. The text comes from books that the Internet Archive has scanned but not digitized. You get to do the digitizing yourself by typing in the word. If enough people complete enough CAPTCHAs on enough sites, pretty soon that adds up to a bunch of books archived for posterity.

I love this idea for several reasons. It’s crowdsourcing at its best. It’s also a perfect example of what 37signals calls judo: break a big task down into many small steps; better yet, take something negative and turn it into a positive. It’s a good cause that happens to be book-related.

When I saw there was a WordPress plugin available, I installed it right here for you all to try out. Now go help save the world.

Plus, I could use more commenters.

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