With the advent of the service applications and their innate standalone nature, Farm Administrators have the ability to delegate responsibility on a per service basis. No longer is the Farm Administrator the only person managing the SharePoint deployment and, as a consequence, becoming a bottleneck for the organization.
In this recipe we can see that services can be assigned to the responsible party. The Central Administration UI will show only the pages for which the Server Administrator has rights.
As an example, search is a critical component to many SharePoint 2010 installations and typically there is a Subject Matter Expert who would be the administrator of this service. Now that person can be assigned the role and that is the only search service they will have access to administer.