Copyright is limited in time (at least in theory!). U.S. government works are not eligible for copyright. Some works do not have sufficient creative element t

Copyright is limited in time (at least in theory!). U.S. government works are not eligible for copyright. Some works do not have sufficient creative element to be covered by copyright, or the other user may be using only the non-covered elements of the work (factual collections, or see recipes). But probably most important, fair use is a limitation to the exclusive rights of copyright, in spite of copyright holders' frequent assertions that "any other use without written consent is prohibited". A use may be fair even against the express wishes of a valid copyright holder, as fair use is not infringement. Factors to be evaluated in fair use include, but are limited to: (1)the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; (2)the nature of the copyrighted work; (3)the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and (4)the effect of the use upon the potential market for or value of the copyrighted work. https://www.copyright.gov/fair-use/ https://www.copyright.gov/fair-use/ https://www.law.cornell.edu/uscode/text/17/107 https://www.law.cornell.edu/uscode/text/17/107 see 107-112 for other limitations of copyright.