"When creating Help for any application, the typical starting point is user profiling. We create user personas, find out what tasks users perform, and identify which tasks are more frequent. We also note users’ preferences for delivery format and language.
However, as applications become more and more sophisticated, their Help systems tend to be equally complex. Some of the reasons for complexity in a Help system are that, more often than not, users have a variety of roles, with different sets of permissions for changing configurable options, and different levels of expertise. The result is an intricate and multilayered Help system. Perhaps the most difficult aspect of managing this complexity is providing Help that is really helpful to expert users.
... How Can You Help Expert Users?
Writing Help for expert users is always a challenge. They quickly cover the basic learning curve for an application and soon find all the typical Help content overly simple. What can we then feed their hungry minds?
* To satisfy their curiosity about the application, explain why in addition to what and how. Consider how Google ranks search results. For expert Google users, knowing why a specific result ranks first has a very high importance. Such users have a natural urge to understand why a result so closely matches their search objective. Explain it to them. You can make viewing such in-depth information optional by providing links to it from procedural Help pages.
* Describe the business rules and system limitations that justify an application’s restrictions. If a field can accept only eight characters, describe the reasons behind that. Expert users are able to appreciate the resource optimization decisions system developers make.
* Include detailed references and background information. Even if your expert users already have sufficient domain knowledge, they always want to enhance it and correlate it with the tasks they perform using the application. You can either add such information to the Help system itself or provide links directing readers to resources on your Web site.
* Exclude some obvious tips and tricks to let expert users satisfy their need for discovery." (Continued via UXmatters) [Usability Resources]