Windows media player is an audio and video player distributed with all recent versions of Microsoft Windows. Microsoft developed WMP to counter the growing popularity of the Real audio and video player by providing streaming audio and video services. Unlike MP3 files, which contain no copyright management features, WMP and its proprietary file format, .WMA, include features that will enable Microsoft to enable a Digital Rights Management (DRM) infrastructure for the distribution of commercial digital content via the Internet. Users will not be able to copy such content, or indeed to access the content, without payment and subsequent authorization. To discourage the use of MP3s, the latest versions of WMP contain only limited support for such files, and MP3 support may be eliminated in future versions of the program. See antitrust, Digital Rights Management (DRM), monopoly, MP3, trusted system, WMA.