Extension:Semantic MediaWiki/Manual/Properties should point from child to parent

The best-practice is for properties to point from child to parent, so the graph ends up looking more like a tree than a web. That best-practice reduces the complexity somewhat by reducing the number of properties to maintain.

For example, many children can have only a few parents. But a few parents can have far more children. When users place properties on a child page, they may only need to place one single property that points to a parent property. If users instead put properties on the parent pages pointing to the children, there could be hundreds or millions of them on one single page. And, worse still, if the child pages get moved or deleted, the parent properties would quickly become out of date. If the properties were on the child pages only, moving or deleting them would not result in problem the same issue.

Also, it is important to note that "properties" are almost synonymous with "pages", because they're basically a special type of page.