Over at Smashing Magazine, Jon Bernbach wrote a nice article exploring cognitive load, "Ways To Avoid Overwhelming Users: Lessons Learned From My High-School Teachers".
Via Gene Smith, the gallery page for the NID Gallery uses an interesting interface navigated with your mouse's scroll wheel. Very intuitive and easy to use.
When you move your mouse towards one wheel or the other (towards people or works), that wheel grows larger and the other wheel shrinks, optimizing the workspace based on the user's preferred mode of navigation.
Enlarging the wheel provides great feedback and makes the individual wheels easier to use, but having the mouse indicate focus can cause problems. I noticed when I moved the mouse out of the way to look at something, the system interpreted this move as choosing one wheel or the other.
Lesson: sometimes the mouse indicates user focus; other times it's in the way.
Typical task flows illustrate the user’s behaviour as they flow through a process, but they do a lousy job showing the behaviour’s context.