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.
Evolutionary biology. Convergent evolution is the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy.