When organizing your site content you might end up with articles that do not belong in any category. These you can add as uncategorized articles. Usually, uncategorized articles contain static content, such as an About Us page or some legal information. However, you can also choose to build your site using uncategorized articles only.
Sometimes, Joomla's powerful multi-level site organization capabilities are just too much. Very small sites—"brochure sites" of some five to ten pages—without secondary page levels, can consist of uncategorized articles only.
Let's say your local yoga teacher asks you to develop a website. She probably wouldn't need much more content than shown in the following diagram:
In this case, there are no layers of content below the menu link level. There will probably be five menu links: Home, About Yoga, About me, Class Schedules, and Contact. Three of these will each point to an article (About Yoga, About Me, and Class Schedules...