If your catalog has a hierarchical structure, you can set up your sites so that customers can navigate to products by traversing the catalog hierarchy. The structure of the catalog hierarchy is determined by the child categories and child products of each category. For example, in a grocery store site, the user might get to a product called Oranges by first selecting the Fruit category, then selecting the Citrus Fruit category (which is a child category of Fruit), and then selecting the Oranges product (which is a child product of Citrus Fruit).