Free Software Foundation
The Free Software Foundation, also known as the FSF, is a non-profit organization that promotes the freedom to study, distribute, create, and modify computer software. Founded by Richard Stallman in 1985, the FSF advocates the publishing of software using a copyleft license. It is headquartered in Massachusetts, USA.
Through the mid-90s, the FSF primarily employed developers to write free software for the GNU (GNU's Not Unix) project. Since then, its employees and volunteers have mostly devoted their time to working on legal issues for the free software community.