Perceivable, Operable, Understandable, and Robust

Joe Dolson recently completed an excellent four part series published on the Practical eCommerce web site. Another great read from Joe,highly recommended. The articles cover the following four fundamental principles of the Web Content Accessibility Guidelines 2.0 (WCAG 2):

1. Is it perceivable?
2. Is it operable?
3. Is it understandable?
4. Is it robust?

Here are the articles:

• New Accessibility Guidelines A “Welcomed Update” (Perceivable)
• New Accessibility Guidelines Part II: Operability
• New Accessibility Guidelines Part III: Understandability
• New Accessibility Guidelines Part IV: Robustness

PS:
Joe was a guest back in 2007 in Podcast: #41: The Definition of Web Accessibility