Jakob Nielsen Answers Usability Questions on slashdot
“Interestingly, research by Jack Carroll at IBM in the 1980s proved that a “training wheels” approach to computers makes people better at understanding the expert features once they get to them. The reason being that users learn the conceptual structure of the system better when they are presented with the smaller set of features first. Not seeing something during initial use of the system would result in better use of the hidden features later.
…In the old days, an operating system was designed to optimize the utilization of the computer’s resources. In the future, its main goal will be to optimize the user’s time.”