Office volume activation is an enterprise feature for volume-licensed editions of Office 2010 and Office 2013 Preview. In addition to the volume activation methods you used for Office 2010 - Multiple Activation Key (MAK) and Key Management Service (KMS), a new volume activation method is available for Office 2013 Preview – Active Directory-Based Activation.
You might have computers at offsite locations that in the past needed to be activated through MAK or by physically connecting to the network through KMS. As long as you are running Office 2013 Preview on a Windows 8 or Windows Server 2012 client computer that is joined to your company’s Active Directory domain, then you can use Active Directory-Based Activation to activate Office 2013 Preview.
When a user joins their computer to the domain, the Active Directory-Based Activation object automatically activates Office 2013 Preview installed on their computer as long as the computer has a Generic Volume License Key (GVLK) installed. No single physical computer is required to act as the activation object, because it is distributed throughout the domain. Note that the same GVLK/KMS host key pair is used for KMS activation, so if the Active Directory-Based Activation attempt should fail, the activation can still take place through a discoverable KMS host. As does KMS, an Active Directory-Based Activation grants a license to the Office 2013 Preview client for 180 days.
For more information about how Active Directory-Based Activation works, see Active Directory-Based Activation Overview.
For more information about how you can use Active Directory-Based Activation to volume activate Office 2013 Preview, see Volume activation methods in Office 2013 Preview.