Works are in the public domain if they are not covered by intellectual property rights at all, or if the intellectual property rights to the works has expired. Examples include the English language, the formulae of Newtonian physics, as well as the works of Shakespeare and the patents over powered flight.[1]
According to Bernt Hugenholtz and Lucie Guibault the public domain is under pressure from the "commodification of information" as item of information that previously had little or no economic value, have acquired independent economic value in the information age, such as factual data, personal data, genetic information and pure ideas. The commodification of information is taking place through intellectual property law, contract law, as well as broadcasting and telecommunications law.[2]
The underlying idea that is expressed or manifested in the creation of a work generally cannot be the subject of copyright law (see idea-expression divide). Mathematical formulæ will therefore generally form part of the public domain, to the extent that their expression in the form of software is not covered by copyright; however, algorithms can be the subject of a software patent in some jurisdictions.[3][4]
Works created before the existence of copyright and patent laws also form part of the public domain. For example, the Bible and the inventions of Archimedes are in the public domain, but copyright may exist in translations or new formulations of these works.
The expiration of a copyright is more complex than that of a patent. Historically the United States has specified terms of a number of years following creation or publication; this number has been increased several times. Most other countries specify terms of a number of years following the death of the last surviving creator; this number varies from one country to another (50 years and 70 years are the most common), and has also been increased in many of them. See List of countries' copyright length. Legal traditions differ on whether a work in the public domain can have its copyright restored. Term extensions by the U.S. and Australia generally have not removed works from the public domain, but merely delayed the addition of works to it. By contrast, a European Union directive harmonizing the term of copyright protection was applied retroactively, restoring and extending the terms of copyright on material previously in the public domain.
Works of the United States Government and various other governments are excluded from copyright law and may therefore be considered to be in the public domain in their respective countries.[5] In the United States, when copyrighted material is enacted into the law, it enters the public domain. Thus, the building codes, when enacted, are in the public domain.[6] They may also be in the public domain in other countries as well. "It is axiomatic that material in the public domain is not protected by copyright, even when incorporated into a copyrighted work."[7]
The definition of public domain is not uniform and may not only include completed works, but also permit ted uses of works still covered by intellectual property rights, such as for example the right to excerpt short quotations in a review. This definition divides areas of private property from areas of the public domain. For example, Mozart's plot is public property, and Britney Spears's music is private property.[8]
In most countries the term for patents is 20 years, after which the invention becomes part of the public domain.
A trademark registration may remain in force indefinitely, or expire without specific regard to its age. For a trademark registration to remain valid, the owner must continue to use it. In some circumstances, such as disuse, failure to assert trademark rights, or common usage by the public without regard for its intended use, it could become generic, and therefore part of the public domain.
Some works may never fully lapse into the public domain. A perpetual crown copyright is held for the Authorized King James Version of the Bible in the UK.[9] While the copyright of the play Peter Pan, or the Boy Who Wouldn't Grow Up by J. M. Barrie has expired in the United Kingdom, it was granted a special exception under the Copyright, Designs and Patents Act 1988 (Schedule 6)[10] that requires royalties to be paid for performances within the UK, so long as Great Ormond Street Hospital (to whom Barrie gave the rights) continues to exist.
Because trademarks are registered with governments, some countries or trademark registries may recognize a mark, while others may have determined that it is generic and not allowable as a trademark in that registry. For example, the drug "acetylsalicylic acid" (2-acetoxybenzoic acid) is better known as aspirin in the United States—a generic term. In Canada, however, "aspirin" is still a trademark of the German company Bayer. Bayer lost the trademark after World War I, when the mark was sold to an American firm. So many copy-cat products entered the marketplace during the war that it was deemed generic just three years later.[11]
Trademarks currently thought to be in danger of being generic include iPod, Jell-O, Band-Aid, Rollerblade, Google, Spam, Hoover, and Sheetrock. Google vigorously defends its trademark rights. Although Hormel resigned itself to genericide,[12] it has fought attempts by other companies to register "spam" as a trademark in relation to computer products.[13]
When a trademark becomes generic, it is as if the mark were in the public domain. Trademarks which have been genericized in particular places include: Formica, Escalator, Trampoline, Raisin Bran, Linoleum, Dry Ice, Shredded Wheat (generic in US), Mimeograph, Yo-Yo, Kerosene, Cornflakes, Cube Steak, Lanolin, and High Octane, (Source: Xerox ad, reprinted in Copyright, Patent, Trademark, ..., by Paul Goldstein, 5th ed., p. 245) as well as Aspirin (generic in the United States, but not in Canada), Allen wrench, Beaver Board, Masonite, Coke, Pablum, Styrofoam, Heroin, Bikini, Chyron, Crapper, Weedwhacker, Kleenex, Hoover (England), Linux (generic in Australia) and Zipper.
