An interesting article in Scientific American entitled “Time to kill off Captchas” caught my eye. As a blind person who is not able to read print I struggle with Captchas on a fairly regular basis. Some sites have no alternative to visual Captchas leaving the blind user no alternative other than to use Webvisum (a Firefox add-in which possesses the capacity to solve some Captchas), however Webvisum can not solve all Captchas leaving the blind user with no alternative other than to seek sighted assistance.
Some sites do have audio alternatives to visual Captchas but the audio is often so garbled that it is virtually impossible to solve the Captcha by listening to it. For the article please visit http://www.scientificamerican.com/article.cfm?id=time-to-kill-off-captchas