Captcha Fail: Researchers Crack the Web’s Most Popular Turing Test

Captcha is the the gold standard for Turing tests on the web: Whenever an online form wants to check if you’re a human being and not a spambot, it asks you to decipher one or two distorted words, presented as images. But what if there was a way for machines to defeat it?

http://mashable.com/2013/10/28/captcha-defeated/