Internal users will require a CAL which is about $100 per user. A forecast of the number of users will be used for Capacity planning for your SharePoint farm. Each server will require a server license. So the number of users may increase the cost of the server licensing.
Another example of convergent evolution is the overall body structure of the shark and the dolphin. A shark is a fish and a dolphin is a mammal. However, their body shape and how they move through the ocean is very similar.
Species may also have similar traits even though they are not related to each other. This usually results because the species live in similar environments and fill similar ecological roles. The structures in this case are known as analogous structures. The process that brings these traits forward is called convergent evolution. Convergent evolution is natural selection that favors the same type of structure in different ancestors.