Free content encompasses all works in the public domain and also those copyrighted works whose licenses honor and uphold the freedoms mentioned above. Because the Berne Convention in most countries by default grants copyright holders monopolistic control over their creations, copyright content must be explicitly declared free, usually by the referencing or inclusion of licensing statements from within the work.
Although there are a great many different definitions in regular everyday use, free content is legally very similar, if not like an identical twin, to open content. An analogy is the use of the rival terms free software and open source, which describe ideological differences rather than legal ones. For instance, the Open Knowledge Foundation's Open Definition describes "open" as synonymous to the definition of free in the "Definition of Free Cultural Works" (as also in the Open Source Definition and Free Software Definition). For such free/open content both movements recommend the same three Creative Commons licenses, the CC BY, CC BY-SA, and CC0.
Copyright is a legal concept, which gives the author or creator of a work legal control over the duplication and public performance of his or her work. In many jurisdictions, this is limited by a time period after which the works then enter the public domain. Copyright laws are a balance between the rights of creators of intellectual and artistic works and the rights of others to build upon those works. During the time period of copyright the author's work may only be copied, modified, or publicly performed with the consent of the author, unless the use is a fair use. Traditional copyright control limits the use of the work of the author to those who either pay royalties to the author for usage of the authors content, or limit their use to fair use. Secondly it limits the use of content whose author cannot be found. Finally it creates a perceived barrier between authors by limiting derivative works, such as mashups and collaborative content
The public domain is a range of creative works whose copyright has expired, or was never established; as well as ideas and facts[nb 1] which are ineligible for copyright. A public domain work is a work whose author has either relinquished to the public, or no longer can claim control over, the distribution and usage of the work. As such any person may manipulate, distribute, or otherwise utilize the work, without legal ramifications. A work in the public domain or released under a permissive licence may be referred to as "copycenter".
Copyleft is a play on the word copyright and describes the practice of using copyright law to remove restrictions on distributing copies and modified versions of a work. The aim of copyleft is to use the legal framework of copyright to enable non-author parties to be able to reuse and, in many licensing schemes, modify content that is created by an author. Unlike works in the public domain, the author still maintains copyright over the material, however the author has granted a non-exclusive license to any person to distribute, and often modify, the work. Copyleft licenses require that any derivative works be distributed under the same terms, and that the original copyright notices be maintained. A symbol commonly associated with copyleft is a reversal of the copyright symbol, facing the other way; the opening of the C points left rather than right. Unlike the copyright symbol, the copyleft symbol does not have a codified meaning.
Projects that provide free content exist in several areas of interest, such as software, academic literature, general literature, music, images, video, and engineering. Technology has reduced the cost of publication and reduced the entry barrier sufficiently to allow for the production of widely disseminated materials by individuals or small groups. Projects to provide free literature and multimedia content have become increasingly prominent owing to the ease of dissemination of materials that is associated with the development of computer technology. Such dissemination may have been too costly prior to these technological developments.
In media, which includes textual, audio, and visual content, free licensing schemes such as some of the licenses made by Creative Commons have allowed for the dissemination of works under a clear set of legal permissions. Not all of the Creative Commons’ licenses are entirely free: their permissions may range from very liberal general redistribution and modification of the work to a more restrictive redistribution-only licensing. Since February 2008, Creative Commons licenses which are entirely free carry a badge indicating that they are "approved for free cultural works". Repositories exist which exclusively feature free material provide content such as photographs, clip art, music, and literature,. While extensive reuse of free content from one website in another website is legal, it is usually not sensible because of the duplicate content problem. Wikipedia is amongst the most well known databases of user uploaded free content on the web. While the vast majority of content on Wikipedia is free content, some copyrighted material is hosted under Fair-use criteria.
Free and open source software, which is also often referred to as open source software and free software, is a maturing technology with major companies utilising free software to provide both services and technology to both end users and technical consumers. The ease of dissemination has allowed for increased modularity, which allows for smaller groups to contribute to projects as well as simplifying collaboration. Open source development models have been classified as having a similar peer-recognition and collaborative benefit incentives that are typified by more classical fields such as scientific research, with the social structures that result from this incentive model decreasing production cost. Given sufficient interest in a software component, by using peer-to-peer distribution methods, distribution costs of software may be reduced, removing the burden of infrastructure maintenance from developers. As distribution resources are simultaneously provided by consumers, these software distribution models are scalable, that is the method is feasible regardless of the number of consumers. In some cases, free software vendors may use peer-to-peer technology as a method of dissemination. In general, project hosting and code distribution is not a problem for the most of free projects as a number of providers offer them these services free.
Free content principles have been translated into fields such as engineering, where designs and engineering knowledge can be readily shared and duplicated, in order to reduce overheads associated with project development. Open design principles can be applied in engineering and technological applications, with projects in mobile telephony, small-scale manufacture, the automotive industry, and even agricultural areas. Technologies such as distributed manufacturing can allow computer-aided manufacturing and computer-aided design techniques to be able to develop small-scale production of components for the development of new, or repair of existing, devices. Rapid fabrication technologies underpin these developments, which allow end users of technology to be able to construct devices from pre-existing blueprints, using software and manufacturing hardware to convert information into physical objects.
In academic work, the majority of works are not free, although the percentage of works that are open access is growing rapidly. Open access refers to online research outputs that are free of all restrictions on access (e.g. access tolls) and free of many restrictions on use (e.g. certain copyright and license restrictions). Authors may see open access publishing as a method of expanding the audience that is able to access their work to allow for greater impact of the publication, or may support it for ideological reasons. Open access publishers such as PLOS and Biomed Central provide capacity for review and publishing of free works; though such publications are currently more common in science than humanities. Various funding institutions and governing research bodies have mandated that academics must produce their works to be open-access, in order to qualify for funding, such as the National Institutes of Health, RCUK (effective 2016) and the EU (effective 2020). At an institutional level some universities, such as the Massachusetts Institute of Technology (MIT), have adopted open access publishing by default by introducing their own mandates. Some mandates may permit delayed publication and may charge researchers for open access publishing. Open content publication has been seen as a method of reducing costs associated with information retrieval in research, as universities typically pay to subscribe for access to content that is published through traditional means whilst improving journal quality by discouraging the submission of research articles of reduced quality. Subscriptions for non-free content journals may be expensive for universities to purchase, though the article are written and peer-reviewed by academics themselves at no cost to the publisher. This has led to disputes between publishers and some universities over subscription costs, such as the one which occurred between the University of California and the Nature Publishing Group. For teaching purposes, some universities, including MIT, provide freely available course content, such as lecture notes, video resources and tutorials. This content is distributed via Internet resources to the general public. Publication of such resources may be either by a formal institution-wide program, or alternately via informal content provided by individual academics or departments.
Any country has its own law and legal system, sustained by its legislation, a set of law-documents — documents containing statutory obligation rules, usually law and created by legislatures. In a democratic country, each law-document is published as open media content, is in principle a free content; but in general there are no explicit license attributed for each law-document, so the license must be interpreted, is a implied license. Only few countries have explicit licenses in its law-documents, as the UK's Open Government Licence (a CC-BY compatible license). In the other countries, the implied license comes from its proper rules (general laws and rules about copyright in government works). The automatic protection provided by Berne Convention not apply to law-documents: Article 2.4 excludes the official texts from the automatic protection. It is also possible to "inherit" the license from context. The set of country's law-documents is made available through national repositories. Examples of law-document open repositories: LexML Brazil, Legislation.gov.uk, N-Lex of EU countries. In general a law-document is offered in more than one (open) official version, but the main one is that published by a government gazette. So, law-documents can eventually inherit license expressed by the repository or by the gazette that contains it.
Prior to 1998, Free Software referred either to the Free Software Foundation (and the watchful, micromanaging eye of Stallman) or to one of thousands of different commercial, avocational, or university-research projects, processes, licenses, and ideologies that had a variety of names: sourceware, freeware, shareware, open software, public domain software, and so on. The term Open Source, by contrast, sought to encompass them all in one movement.