6.3. Understanding Active Directory Domain Services
With Active Directory Domain Services (AD DS), you manage objects (users, computers, printers, etc.) on a network. Active Directory is the database that stores all of your domain objects. In a Windows Server 2000, 2003, or 2008 network, you can not have a domain without Active Directory.
6.3.1. Introducing the New Domain Services Features in Windows Server 2008
Many new AD DS features have been added in Windows Server 2008. These features improve the security and efficiency of deploying and administering AD DS.
User interface improvements
Domain services are easier to install using the updated Installation Wizard for AD DS. Administrators can set up domain controllers anywhere in the organization. ...