Tikiwiki is feature rich, and many features overlap, especially when it comes to how many ways you can organize content. In designing a tikiwiki site you have to decide early what kind of Navigation Overview is most appropriate and then use menus, hyperlinks, topics, structures and themes accordingly.
Are you building a knowledge base with a more or less permanent table of contents? - use categories.
Are you collaboratively writing documents that need to be viewed in order, or published as a hard copy (PDF) - use structures.
Are you hosting discussions, blogs or forums where topics tend to come and go a lot? - use regular hypertext and wiki links, rather than getting bogged down in creating hierarchies that nobody will care about tomorrow.
Are you creating objects/pages that a time sensitive status - use trackers.Are you using tikiwiki with multiple groups who need access to separate or private areas? - use structures or groups