CopyleftCopyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, freedoms refers to the use of the work for any purpose, and the ability to modify, copy, share, and redistribute the work, with or without a fee. Licenses which implement copyleft can be used to maintain copyright conditions for works ranging from computer software, to documents, art, scientific discoveries and even certain patents.
Public domainThe public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because no one holds the exclusive rights, anyone can legally use or reference those works without permission. As examples, the works of William Shakespeare, Ludwig van Beethoven, Leonardo da Vinci and Georges Méliès are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired.
Copyright abolitionCopyright abolition is a movement to abolish copyright, for example by repealing the Statute of Anne and all subsequent law made in its support. The notion of anti-copyright combines a group of ideas and ideologies that advocate changing the current copyright law. It often focuses on the negative philosophical, economic, or social consequences of copyright, and that it has never been a benefit to society, but instead serves to enrich a few at the expense of creativity.
Public-domain softwarePublic-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, or sold even without any attribution by anyone; this is unlike the common case of software under exclusive copyright, where licenses grant limited usage rights.
Criticism of copyrightCriticism of copyright, or anti-copyright sentiment, is a dissenting view of the current state of copyright law or copyright as a concept. Critics often discuss philosophical, economical, or social rationales of such laws and the laws' implementations, the benefits of which they claim do not justify the policy's costs to society. They advocate for changing the current system, though different groups have different ideas of what that change should be.
Free-culture movementThe free-culture movement is a social movement that promotes the freedom to distribute and modify the creative works of others in the form of free content or open content without compensation to, or the consent of, the work's original creators, by using the Internet and other forms of media. The movement objects to what it considers over-restrictive copyright laws. Many members of the movement argue that such laws hinder creativity. They call this system "permission culture".
Public copyright licenseA public license or public copyright licenses is a license by which a copyright holder as licensor can grant additional copyright permissions to any and all persons in the general public as licensees. By applying a public license to a work, provided that the licensees obey the terms and conditions of the license, copyright holders give permission for others to copy or change their work in ways that would otherwise infringe copyright law. Some public licenses, such as the GNU GPL and the CC BY-SA, are also considered free or open copyright licenses.
Public-domain-equivalent licensePublic-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses. No permission or license is required for a work truly in the public domain, such as one with an expired copyright; such a work may be copied at will.
Permissive software licenseA permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. the most popular free-software license is the permissive MIT license.
Creative Commons licenseA Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted "work". A CC license is used when an author wants to give other people the right to share, use, and build upon a work that the author has created. CC provides an author flexibility (for example, they might choose to allow only non-commercial uses of a given work) and protects the people who use or redistribute an author's work from concerns of copyright infringement as long as they abide by the conditions that are specified in the license by which the author distributes the work.
