Richard Stallman in the context of "Hacker (programmer subculture)"

Open-source licenses are software licenses that allow content to be used, modified, and shared. They facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative works. Free and open-source licenses use these existing legal structures for an inverse purpose. They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications. These criteria are outlined in the Open Source Definition.

After 1980, the United States began to treat software as a literary work covered by copyright law. Richard Stallman founded the free software movement in response to the rise of proprietary software. The term "open source" was used by the Open Source Initiative (OSI), founded by free-software developers Bruce Perens and Eric S. Raymond. "Open source" emphasizes the strengths of the open development model rather than software freedoms. While the goals behind the terms are different, open-source licenses and free-software licenses describe the same type of licenses.

The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985. The organization supports the free software movement, with its preference for software being distributed under copyleft ("share alike") terms, such as with its own GNU General Public License. The FSF was incorporated in Boston where it is also based.

From its founding until the mid-1990s, FSF's funds were mostly used to employ software developers to write free software for the GNU Project and its employees and volunteers have mostly worked on legal and structural issues for the free software movement and the free software community. Consistent with its goals, the FSF aims to use only free software on its own computers.

Open collaboration refers to any "system of innovation or production that relies on goal-oriented yet loosely coordinated participants who cooperate voluntarily to create a product (or service) of economic value, which is made freely available to contributors and noncontributors alike." It is prominently observed in open source software, and has been initially described in Richard Stallman's GNU Manifesto, as well as Eric S. Raymond's 1997 essay, The Cathedral and the Bazaar. Beyond open source software, open collaboration is also applied to the development of other types of mind or creative works, such as information provision in Internet forums, or the production of encyclopedic content in Wikipedia.

The organizing principle behind open collaboration is that of peer production. Peer production communities are structured in an entirely decentralized manner, but differ from markets in that they function without price-based coordination, and often on the basis of volunteering only. Such communities are geared toward the production of openly accessible public or "common" goods, but differ from the State as well as charity groups in that they operate without a formal hierarchical structure, and rest solely on the construction of a rough, evolving consensus among participants.

The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or copyleft licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first copyleft license available for general use. It was originally written by Richard Stallman, the founder of the Free Software Foundation (FSF), for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. The licenses in the GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. The GPL states more obligations on redistribution than the GNU Lesser General Public License and differs significantly from widely used permissive software licenses such as BSD, MIT, and Apache.

Historically, the GPL license family has been one of the most popular software licenses in the free and open-source software (FOSS) domain. Prominent free software programs licensed under the GPL include the Linux operating system kernel and the GNU Compiler Collection (GCC). David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving the contributing programmers some assurance that their work would benefit the world and remain free, rather than being potentially exploited by software companies who would not be required to contribute to the community.

The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run, study, modify, and share copies of software. Software which meets these requirements, The Four Essential Freedoms of Free Software, is termed free software.

Although drawing on traditions and philosophies among members of the 1970s hacker culture and academia, Richard Stallman formally founded the movement in 1983 by launching the GNU Project. Stallman later established the Free Software Foundation in 1985 to support the movement.