Interesting although I would differentiate between visual and aural
captcha. Most of the issues you mentioned pertain to blind access to
visual captchas, not audible. The fact that many sites fail to implement
audio captcha is not the fault of captcha in of itself. Also, the
difficulty in discerning audio captcha is similar to the difficulty
parsing visual captchas. None of them are easy for good reason. Lowering
the cognitive bar lowers the barrier to spammers. I'll dig up my
response to the w3c on this from last year and send that along.
CB
Greg Kearney wrote:
For my continuing series on web design for accessibility I discuss
CAPTCHA the design and usability issues they represent as well as
offering an accessible alternative. For the page go to:
http://www.cucat.org/projects/navigation/captcha/index.php
To read my other papers on similar topics go to:
http://www.cucat.org/projects/design.php
Thanks for looking.
Greg Kearney
535 S. Jackson St.
Casper, Wyoming 82601
307-224-4022
[EMAIL PROTECTED]
