

reCaptcha - Block spam and digitize books - Readmore
http://www.techcrunch.com/2007/09/16/recaptcha-using-captchas-to-digitize-books/

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bharath
Seems like yet another application of Luis Von Ahn's notion of "human
computation". Using human cycles to solve computationally intractable
problems:

<http://tinyurl.com/2wtrco>

Its interesting to note that given the usability constraints of captchas
people will almost always go for a "more usable" and algorithmically complex
alternative if one is available. The use of akismet to stop comment spam in
blogs in a case in point.

