I read an interesting article a while ago about
Luis von Ahn who is most famous for inventing the Captcha. You probably know what a Captcha is (those blurry bits of text you have to type in to prove you're a human), but you probably don't know that CAPTCHA is an acronym that stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart.
An example captcha...
The same guy also came up with a way to turn the difficult computer task of labeling images are into
an addictive and fun game, which Google purchased to help with the quality of image search. It's not much of a leap to see that humans can do this more easily than computers, but to turn it into a game that is not only fun enough that people will actually want to play it, but that also validates the input at the same time, is pretty impressive.
What I find particularly neat is one of his latest ideas, which he calls reCaptcha. Here's an example:
It doesn't look like anything too spectacular but there's a hidden trick to it. One of the words is actually a captcha, but the other word is a word which the Internet Archive's public domain book scanning project had difficulty recognizing. Now the captcha doesn't just make sure you're a human (through the known word), it also collects information towards a useful goal. The time difference to type two words instead of one is minimal so by distributing the project of figuring out the words a computer can't recognize we can have millions of people contribute without even realizing they're helping out.
What can I say... I'm impressed.
