A key design characteristic of SharePoint Server is its scalability. Any given SharePoint installation can be designed for a small user intranet, a large enterprise, or a public web site. It can be focused on serving web page requests, dedicated to search services, or tuned for other applications such as Microsoft Excel or BCS.
One of the only constants in IT is change, and SharePoint is no exception to this rule. An effective SharePoint design accounts for the current and expected requirements of an organization. After the initial design is implemented, the SharePoint farm can then be modified and tuned to suit the changing requirements of the business.