A DRM developer wrote to me concerned about Apple CEO Steve Jobs' anti-DRM support, and the role and future of DRM. My response has been broken into a few digestible parts of the next few days.
> Part 1 - Where It Fits
> Part 2 - Who's in Control
> Part 3 - The Future of DRM

PART 1 - WHERE IT FITS

DRM is part of a larger effort by content providers and distributors to identify and control their content. While it's a fundamental locus for content control, it's not the only one.

1. Internal Control (DRM) - the use (authorization) and control (playing, copying, writing to CD, etc) of media inside a controlled environment. This can be in the file, in the client (like the media player), via server, in the OS (as Microsoft would try to do), or some combination. I would consider any such strategy that enforces publisher business rules to be DRM.

2. Acquisition Control - when external media is introduced to a controlled environment like a media player or downloaded via P2P. Control is exerted by restricting imported media (like blocking all mp3 files) or qualifying it, such as by filtering out copyrighted files.

3. Interdiction Control - making unauthorized content difficult for other parties to obtain. One example is inserting bogus files on P2P networks.