In this chapter, we've examined three types of explicit user assistance: passive assistance that is built into a system's user interface, reactive assistance that occurs as a result of some user actions, and proactive assistance that is initiated by the system itself.
We began by looking at three types of passive assistance: mnemonic access keys, ToolTips, and status bars. We then examined reactive assistance, which is usually implemented in the form of on-line help or What's This? Tips, but can also include audible feedback and should include error messages. Finally, we looked briefly at the new area of proactive assistance and user training.