First Principles of Interaction Design Look at the user's productivity, not the computer's. People cost a lot more money than machines, and while it might appear that increasing machine productivity must result in increasing human productivity, the opposite is often true. In judging the efficiency of a system, look beyond just the efficiency of the machine.
Basic Principles of Interaction for Learning in Web-Based Environment
10 Heuristics for User Interface Design
Ergonomie web illustrée