The document discusses how to plan an appropriate site topology in SharePoint. It explains that site collections and sub-sites provide containers for content and each have pros and cons. The key is finding a balance between too many deep sub-sites versus too few top-level site collections. When planning a topology, considerations include governance, quotas, content types and amounts, administrators, and importance of information. Examples are provided of both deep and flat topologies as well as when to use site collections versus sub-sites.