As you know, CAPTCHA is a completely automated public Turing test to tell machines and humans apart, designed to prevent spammers from automatically sending commercial messages to websites and people by requiring them to read unreadable words and numbers.
However, there is a problem with CAPTCHA – the matter is that it hinders people with vision impairments to the point that they can’t use certain online services. A number of organizations, including Blind Citizens Australia, Able Australia, Media Access Australia and the Australian Deaf-Blind Council, are calling on Internet services to stop using CAPTCHA, launching a petition with the Australian Communications Consumer Action Network.
It seems that even when CAPTCHA uses audio files along with the strings of letters, the users with disabilities find them just as tough. Indeed, the recent research revealed that dyslexic, color-blind and older users usually find CAPTCHA hard to get through too. As a result, the technology may in fact contravene the country’s Disability Discrimination Act.
Instead of using CAPTCHA critics suggest using emails to activate and verify Internet users. In the meantime, the W3C online standards organization has already commented that the technology in question has become less effective as an anti-spam measure. It turned out that character and image recognition software is already able to defeat it.