MMC ( Mandatory Managed Copy )
Mandatory Managed Copy is part of the Advanced Access Content System (AACS) specification and is supported by both HD DVD and Blu-ray Disc. Mandatory Managed Copy basically means that a consumer will be able to somehow make digital copies of the data on a disc for use with a home theater system, or even make digital copies for portable players. While it is part of the AACS specification it still makes content companies nervous about the problems it could cause.
MMC may be revoked if such studios as Fox have their way with restrictions such as BD+. BD+ is the name given to an experimental Digital Rights Management (DRM) mechanism that will be included on BD-ROM discs. The Blu-ray Disc Association was forced into providing this extra layer of protection following pressure from Fox. The HD DVD group did not agree to provide Fox with such a DRM over AACS. The fears about BD+ surround the possibility of studios like Fox theoretically being given the power to restrict Mandatory Managed Copy (a system that allows users to make digital copies of movies and send them around a home network).