Content is added to the knowledgebase in the form of articles.
Users with author or contributor access create the articles. They work on them in draft mode until the article is complete.
If they are authors, they can publish direct to the knowledgebase. If they are contributors they can only create drafts and articles that are 'pending' approval and these must then be 'published' by a supervisor or administrator.
Every knowledgebase category can have a "Supervisor". If an article is placed into pending in a category with a supervisor, then the supervisor receives an email notification to approve the article. If there is no supervisor for the category then a notification is sent to the knowledgebase administrator instead.