As excerpted from Builder Magazine's (the magazine of the National Association of Home Builders) article entitled "The Principles of Universal Design: Seven Rules to Build By" :

Principle 1: Equitable use. The design is useful and marketable to people with diverse abilities, providing the same means of use for all users without segregating or stigmatizing.

Principle 2: Flexibility in use. The design accomodates a wide range of individual preferences and abilities, providing a choice of methods of use and adaptability to the user's pace.

Principle 3: Simple and intuitive use. The design is easy to understand regardless of the user's experience, knowledge, language skills, or current concentration level, including effective prompting and feedback during and after the task is completed.

Principle 4: Perceptible information. The design communicates necessary information, using a variety of modes (visual, verbal, tactile), making it easy to give instruction or direction for proper use.

Principle 5: Tolerance for error. The design minimizes hazards and consequences from accidental or unintended use. Hazardous elements are eliminated, isolated, or shielded; fail-safe features and adequate warnings are provided.

Principle 6: Low physical effort. The design allows the user to maintain a neutral body position while minimizing repetitive action and sustained physical effort.

Principle 7: Size and space for approach and use. The design accomodates a variety of physical sizes, postures, and mobility, including a clear line of signt from both a seated and standing position, and all components are within reach.

Coming tomorrow: How these principles relate to information and web design.