Note of DRM

DRM:
[Game industry]
SecuROM - require authentication via online server
SafeDisc - a copy protection program for Microsoft Windows applications and games that are distributed on optical disc.It aims to restrict unauthorized disc duplication
persistent online authentication
software tampering - some interesting enough handling against possible pirated games, such as activating a invincible enemy in the game or do whatever weird or funny thing to the users.

[document]
E-DRM/ERM/IRM- prevent unauthorized use of propriestary documents.

[e-books]
Electronic books read on a personal computer or an e-book reader typically use DRM technology to limit copying, printing, and sharing of e-books. E-books are usually limited to a certain number of reading devices and some e-publishers prevent any copying or printing.

[film]
CSS(content srambling system): used by DVD forum. A encryption/decryption mechanism that requires a DVD device to equipped with the ability to decrypt in order to play it.
Windows Media DRM: Define a right management language on how a user could do with the media.
AACS(Advanced Access Content System): used by HD DVD and blueray DVD but hacked.

[music]
Each company or organization has its own DRM system and not interoperable. Sure those who adopt the same DRM system can share the content, but not on some popular players such as Apple ipods.
A suggestion is that allowing formet-shift among different DRM-protected contents should be possible in the future for users to do it privately.
However, more and more companies turn to DRM-free downloading.

[television]
broadcast flag: used to decide if a stream can be recorded.
Content Protection and Copy Management group under DVB (DVB-CPCM): not ready yet

Reference links
http://en.wikipedia.org/wiki/Digital_rights_management 
http://stackoverflow.com/questions/822468/is-there-an-open-source-drm-solution
http://www.techdirt.com/articles/20081028/0342002668.shtml
http://www.zdnet.com/blog/hardware/the-idea-of-open-source-drm-makes-me-want-to-vomit-with-rage/2844