Therefore, allow one or more ParentPages to be selected from the child's BackLinks. When a page is first created, use the page it was created from as its initial parent. Display a page's parents in the title bar for the benefit of the reader.
But, providing sensible PeerReview of changes to ParentPages may be impossible on many wikis without substantial changes to their RecentChanges design. Also, a page cannot be categorized without editing the category page, unlike simple ReverseIndex-based categories.
(Idea originally described on ZWiki:WikiStructuringIdeas)