We are designing our new HelpSpot system right now, and one area that the documentation is (intentionally) vague on is exactly how categories and keywords should be configured. Naturally, there are many ways of skinning the support cat, so this really is a decision that needs to be made on a case-by-case basis.
Having said that, though, it would be very, very useful for new users to have access to a set of white papers describing how a number of different firms set up their categories and keywords. Just being able to read through 5 or 10 different setups would be massively helpful for someone coming to the system cold.
The format of these would be a very brief description of the company (industry, number of clients, number of techs and a brief of the type of support they provide), followed by the categories and keywords they use. If it also includes “here’s how the categories get used”, that’s fine - but it wouldn’t be necessary. Just knowing the category names would be great.