Basically, the CAPTCHA is made up of two words — one of which is known to Carnegie, and one of which isn't. If the user correctly deciphers the known CAPTCHA, then the unknown CAPTCHA is assumed to be correct. Well, almost. Two different users must give the same answer to the same unknown CAPTCHA before it is taken off the list.
Clever, IMHO, and might at least give us some consolation as we squint at those damn characters.
Of course, all this could be screwed if too many bots starting using the same algorithm to incorrectly guess the answer..."
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