DRM, or “Digital Rights Management” is a catch-all term for any technological measures, usually but not always software-based, that are put in place to protect copyrighted content.
DRM usually works by restricting access to the content in some way. DRM applies to all would-be users of the content, event those who have purchased it, or the right to access it, legally. Most DRM techniques are also easily circumvented by a technically adept and/or determined user. Therefore, DRM has the net effect of inconveniencing legitimate users, sometimes seriously, and being a minor inconvenience at best for professional criminal users. Additionally, certain forms of DRM can raise serious privacy concerns, as well as call into question the very idea of “ownership” of digital information.
For these reasons, DRM has been heavily criticized, and there may be a trend in the content industry away from its use. For example, after many complaints from users, iTunes and Amazon now offer DRM-free music downloads, and most of the major record labels have given up on DRM for digital music. However, the Recording Industry Of America, and the Motion Picture Industry of America have both said that they see DRM being part of their business models for the foreseeable future.