accessibility of new web services

Hi

 

I am currently looking at the accessibility implications of some of the more
recent web applications and tools. My general theme is that, while it is
great to push the boundaries and try new ideas, we must also be mindful of
the needs of people who rely on assistive technologies to access these
services. For example, I know that the CAPTCHA on Twitter causes problems
for some web users.

 

I am really interested in things like blogs, microformats, social
bookmaking, AJAX etc. Can anyone suggest any sites or examples that might be
useful?

 

Many thanks

Roger