So I saw a really cool use today.
CAPTCHA are those little security messages that spam bots have a tough time deciphering, and thus slow down spammers from maiking fake accounts. This does require users to spend a little time deciphering the puzzles too.
reCAPTCHA uses 2 word puzzles. One is knwon, and the second word is supplied from texts that are being digitized where the software has a difficult time recognizing the word.
http://en.wikipedia.org/wiki/ReCAPTCHA
The article says that this method is applying 12,000 manhours a day, or roughly the equivalent output of a 1,500 person company.
Now where is my check for $1.13...