With the release of Windows Server 2012, Microsoft brings its experience in building and operating public clouds to the server platform for private clouds. It offers customers scalable, dynamic and multitenant-aware cloud infrastructure that helps users connect across-premises. As a result, IT can respond to business needs with greater agility and efficiency, and the mobile workforce is able to access personalized work environments from virtually anywhere.
The Windows Server 2012 product line-up has been streamlined and simplified, making it easier for customers to choose the edition that is right for their needs.
Datacenter edition for highly-virtualized private cloud environments.
Standard edition for non-virtualized or lightly virtualized environments.
Essentials edition for small businesses with up to 25 users running on servers with up to two processors.
Foundation edition for small businesses with up to 15 users running on single processor servers
Running instances can exist either in a physical operating system environment (POSE) or a virtual operating system environment (VOSE). Edition Running instances in POSE Running instances in VOSE
*When a customer is running all allowed virtual instances, the physical instance may only be used to manage and service the virtual instances. For information about licensing in virtual environments, see the Microsoft Volume Licensing Brief: Licensing Microsoft Server Products in Virtual Environments white paper.
**Essentials can be run in either a physical or virtual operating system environment “1 or 1.”
Edition comparison by server roles
Here is a summary of key server roles by edition.
Edition comparison by feature
Here is a summary of key server features.
So basically Windows Server 2012 Licensing Changes big time and much easier. Hyper-v is there only in datacenter and standard edition.