The Free Software Foundation (FSF) is a non-profit corporation, founded in the US in 1985 with the stated mission "to promote computer user freedom and to defend the rights of all free software users." Free software is defined by the FSF as software with freely accessible source code that can be run, copied, distributed, studied, changed and improved without restrictions. The Free Software Foundation is active worldwide, and claims to have 3,000 active members in 48 countries. It promotes and supports the development and adoption of free software, and campaigns against what it perceives as restrictions of software freedom, like proprietary software and user interface copyright. Recent software development efforts by the FSF have focused on its high priority projects, including the development of a free software Flash player, free software for PDF management and video editing, and free alternatives to Skype and Google Earth.
On its website, the Free Software Foundation maintains the Free Software Definition. This is a list of four freedoms the FSF considers essential for users to have if a program is to be considered free software: the freedom to run the program for any purpose; the freedom to study and make changes to the program's source code; the freedom to redistribute copies of the software; and the freedom to distribute copies of modified versions of the program. Other activities by the FSF include publishing a free software license and hosting free software projects on its servers.
The most important software development project supported by the Free Software Foundation is the GNU-project, a free software operating system that was completed in 1992. The organization is still involved in the development of free software for this project, but much of its focus has shifted to political initiatives, legal issues and raising public awareness. For example, the FSF campaigns against software patents and Digital Rights Management (DRM), which it sees as infringements on software freedom.
The FSF also promotes the free audio format OGG+Vorbis as an alternative to mp3 and AAC, and has sponsored campaigns against certain proprietary software, including Windows Vista, the so-called "BadVista" campaign. Some people in the computer industry have criticized these campaigns for being too negative, and claim that free software is not always a credible alternative for users. The Free Software Foundation often works together with other organizations in the free software movement. This includes the Software Freedom Law Center (SFLC), the Electronic Frontier Foundation (EFF), and the League for Programming Freedom (LPF).