If an organization would like to use a hosted service where the dedicated hardware is assigned to the organization, there are just few changes with regard to the Microsoft licensing. Existing volume licensing agreements can essentially be used to purchase a hosted service.
However, if it’s an environment, where virtual machines (VMs) are shared with third parties, it is not possible to take volume licenses and adapt those. This, for instance, is the case in a hosted Exchange service.
Below is a brief overview of each scenario for Microsoft licensing in relation to a hosted service: