Discusses Fitts's UI Law and how it applies to designing Web pages.
Interface design is difficult in part because everything requires interpretation.
A design that works for one task or one user might not be appropriate for another. In other types of engineering, like architecture or bridge building, designers can always rely on laws of physics and gravity to make designs work. There is at least one immutable rule for interface design that we know about, and it's called Fitts's Law. It can be applied to software interfaces as well as Web site design because it involves the way people interact with mouse or other pointing devices. Most GUI platforms have built-in common controls designed with Fitts's Law in mind.