I was reading a blog article about writing documentation, and I came across this quote:
The purpose of technical documentation is to take someone who has never seen your project, teach them to be an expert user of it, and support them once they become an expert.
While that's a great definition, I think there needs to be a distinction between technical documentation and what you're trying to accomplish writing Salesforce documentation for your end users.

Some online knowledge base software (e.g. wikis) assume end-users know the questions they want to ask, so the software is optimized for search. The problem is, this approach leaves out end-users who don't know what question to search with, or what the options are.
When you hire new employees (or your existing employees change roles), getting them up and running can be a headache - which is why I recommend creating a quick onboarding guide that you and your users can reference.