Take responsibility for the user’s experience

• Design with understanding that a user’s needs change frequently while they work and play.

Principle of non-preemption

• “Individual interactive programs operate in a non-intrusive manner with respect to the user’s activities. The system does not usurp the attention and prerogatives of the user. A program responds to the user’s stimuli, but then quietly retains its context and logical state until the user elects to interact with the program again…” – From Deutsch & Taft 1980 “Requirements for an experimental programming environment”
• “…Human attention is the most valuable and scarcest commodity in human computer interaction.” – From Horvitz, Jacobs, Hovel Attention-Sensitive Alerting

Principle of Least Astonishment

• Or “uniformity in command interface” – From Deutsch & Taft 1980 Requirements for an experimental programming environment

Design a self-teaching interface for beginners, and an efficient interface for advanced users, but optimize for intermediates

• Balance learnability and discoverability with utility

Don’t unnecessarily rely on metaphor

• Especially mechanical-age, which may be antiquated to many users, and eventually all users.

Less is More

• Reduce visual, memory, intellectual, and motor work (and complexity)

Be considerate and forgiving

• It is better to offer to undo a mistake than to ask a user if they are “sure.”

The technology should act as a mediator

• Be the vehicle, not the destination

Strive for transparency

I have to say I 100% agree with them (even though I’m disappointed not to see the last one already applied – take the lack of error messages in some parts of the current Gnome, for example).

Is there any other good principle you’d add to these ?