Team Foundation Server Users
Usually, you will want to assign individual users to groups, and assign permissions based on these groups. Group permissions are more easily managed than those for individual users as they consolidate permissions into an optimal set of well-defined roles.
In certain situations, however, you may find it desirable to assign a user permissions directly on the server or on a project instead. This can be useful when you need to assign someone to a backup function, such as granting another person the Publish Test Results permission while the testing lead is on vacation. For security purposes, such temporary permissions should be removed when the need for them no longer exists.