It's virtually impossible—and certainly impractical—for
anyone to learn and remember everything there
is to know about the computer hardware and software they use to
do their job. Nearly every computer user needs help at one time
or another.
Online help, unlike a printed manual, has the power of the
computer at its disposal. Most importantly, this power makes it
possible to adapt the information to the user's current context.
Context-sensitive help provides just enough
help to get the user back on task. In developing your online help,
remember that users need different types of help at different times.
By anticipating users' questions, you can design your application
help to respond in a logical and intuitive manner.