For most of the history of Anglo-American copyright law, copyright was an opt-in system: Authors had to jump through certain regulatory hoops if they wanted to prevent others from copying their works without consent. These threshold formalities included registering their works with a government agency, affixing a notice to published copies, depositing exemplars with a centralized library, and more. A failure to comply with the requirements usually meant a diminution in the authors’ copyright entitlement – and in some cases a wholesale forfeiture, under which the works would pass immediately into the public domain.
After some 200 years, however, U.S. copyright abandoned its formal requirements. Beginning in 1976 and culminating in 1989, Congress responded to complaints from authors (who had sometimes lost protection due to what they viewed as a technicality) and to pressure to join the international copyright community (which forbade most formalities). Copyright law accordingly underwent a conversion from opt-in to opt-out. [...]
James Gibson, The Rebirth of Copyright As an Opt-In System, The Media Institute (Mar. 10, 2010), available at https://www.mediainstitute.org/2010/03/10/the-rebirth-of-copyright-as-an-opt-in-system/.