The issues surrounding online copyright infringement continue to be the subject of much debate, and the rules and regulations regarding online copyright infringement continue to change as the Internet changes. One of the more controversial issues is the use of Digital Rights Management, also known as DRM. DRM refers to technologies that control or limit access to copyrighted works. Corporations such as Microsoft, Apple, and Sony are among the many who use Digital Right Management to impose limitations on how consumers may use their copyrighted materials. Defenders of Digital Rights Management argue that DRM is needed to guard against online copyright infringement and possible revenue loss. Opponents of DRM technologies argue that access controls are overly restrictive and may amount to anti-competitive practices. The Free Culture Movement is a term used to describe the social movement that opposes restrictive copyright policies. The Electronic Frontier Foundation and the Free Software Foundation are two of the key groups in the Free Culture Movement. Proponents of the Free Culture Movement argue that DRM and other restrictive copyright policies hinder creativity, and think that there should be more freedom online in regard to creative works.