In printed books, a good index provides an outline of the book’s contents and helps readers quickly find specific information. Indexes also associate related information in a book; when several pages are listed under a common index entry, readers know that the information on those pages is related in some way.
In Windows Help, the Search feature provides a type of “electronic index,” similar to a book index, in which users look up words in the index to find specific information quickly. By typing a keyword or choosing one from the keyword list in the Search dialog box, users can see all the topics associated with a keyword and go directly to one of the associated topics. Because keyword search is a fast way for users to find information, you should consider assigning keywords to most topics in your Help file. Likewise, if you do not want users to access certain topics through the Search facility, you should not assign any keywords to those topics.
Help makes it easy to add keywords to topics. However, much of the work in creating a good keyword index involves analysis and planning. When you create an index for a book, you need to plan the index entries carefully, eliminate duplicate or ambiguous entries, and apply the entries consistently to all pages of the book. The same issues apply to Help keyword indexes.