Web Accessibility principles

I was going through my juniors work on Ruby on Rails. I was helping them to build some interesting web applications. And then the discussions lead to design, usability and accessibility of the application. As they don't have enough exposure on web applications, I quoted few articles and books to say UI is as important as functionality. Of which, I highlighted the "Ten Principles for Web Accessibility" from "Pragmatic Design & Accessible Web Sites" by Jeremy J. Sydik.

1. Avoid making assumptions about the the physical, mental, and sensory abilities of your users whenever possible.
2. Your users’ technologies are capable of sending and receiving text.
   That’s about all you’ll ever be able to assume.
3. Users’ time and technology belong to them, not to us. You should
   never take control of either without a really good reason.
4. Provide good text alternatives for any non-text content.
5. Use widely available technologies to reach your audience.
6. Use clear language to communicate your message.
7. Make your sites usable, searchable, and navigable.
8. Design your content for semantic meaning and maintain separation between content and presentation.
9. Progressively enhance your basic content by adding extra features. Allow it to degrade gracefully for users who can’t or don’t wish to use them.
10. As you encounter new web technologies, apply these same principles when making them accessible.
    

Link to Book:
http://www.pragprog.com/titles/jsaccess/design-accessible-web-sites