I ran into an interesting project this morning called reCAPTCHA. In the spirit of distributed computing solutions, such as folding@home, it tackles a difficult problem by splitting it up and farming the pieces out. What makes this interesting is that instead of having computers solve the problem, people do.
ReCAPTCHA actually tries to solve two problems. The reCAPTCHA project pipelines the unrecognizable words from a book scanning OCR effort into a freely available web service for verifying your humanity, a CAPTCHA. Instead of each CAPTCHA puzzle being a necessary but regrettable waste of human effort, reCAPTCHA harnesses this otherwise lost resource. How brilliant is that!
The web service looks very interesting to me. I’m due to revisit a submission form soon that contains a CAPTCHA that I wrote several years ago that I know has been broken. The system contains a very extensive blacklisting system, so the weakness of the CAPTCHA has never been enough of a problem to warrant its replacement, but I’m curious to see what difference this service will make.