What Accessibility Is and Isn't
Accessibility focuses not only on people with disabilities, but on ANYONE who may experience difficulty in reading or navigating a website. For example, users with a very old computer system, a visually impaired user, or even down to someone with a broken arm who can't use a mouse! See wikipedia's definition for one of the best explanations. w:Web_accessibility
Usability is often confused with Accessibility. Although hard to define, it comes at a more general approach- ensuring everyone (disability, disadvantages, or totally able) is able to use the site in the most straightforward manner. This could include, having things that are easy to find in prominent spots, ensuring common or repeated tasks on a website can be shortcutted etc. You'll often hear about GUI (graphical user interface) and whenever I think of usability I think about improvements I would make to the GUI.
As a summary-
- Accessibility- ensuring information is physically retrievable
- Usability- ensuring the information is retrieved in an easy and simplified manner
Resources on Accessibility
- - Great collection of articles on accessibility on the web
- - A website that showcases 'accessible, usable web sites built with universality and standards in mind'. It also has a very detailed list of criteria which these sites have met and/or surpassed to received this recognition.
- - A huge mega-reference (nearly 6,000 links) of information and articles about web design and development. It is dedicated to disseminating news and information about web design and development with sections on accessibility, books, tools, CSS, web standards, user experience, and much more.