CAPTCHA (standing for Completely Automated Public Turing test to tell Computers and Humans Apart) must have seemed like a good idea when it was first invented in 2000. Spam was beginning to become a major problem on the web and a method was needed to fight back. CAPTCHA at first glance seems ideal: a distorted image that would be instantly recognisable by humans yet incomprehensible to machines. Place some letters in the distorted image and get the user to type them back and bingo: you’ve stopped your spam problem.
Recently myself and Robin attended the Accessibility 2.0 conference. The agenda of the day was accessibility on the Internet in the ever changing world of rich media websites and social networking.