The Copyright Term Extension Act (CTEA) of 1998 – alternatively known as the Sonny Bono Copyright Term Extension Act, Sonny Bono Act, or pejoratively as the Mickey Mouse Protection Act – extended copyright terms in the United States by 20 years. Before the Act (under the Copyright Act of 1976), copyright would last for the life of the author plus 50 years, or 75 years for a work of corporate authorship; the Act extended these terms to life of the author plus 70 years and for works of corporate authorship to 120 years after creation or 95 years after publication, whichever endpoint is earlier. The Act also affected copyright terms for copyrighted works published prior to January 1, 1978, also increasing their term of protection by 20 years, to a total of 95 years from publication.
This law effectively 'froze' the advancement date of the public domain in the United States for works covered by the older fixed term copyright rules. Under this Act, additional works made in 1923 or afterwards that were still copyrighted in 1998 will not enter the public domain until 2019 or afterwards (depending on the date of the product) unless the owner of the copyright releases them into the public domain prior to that or if the copyright gets extended again. Unlike copyright extension legislation in the European Union, the Sonny Bono Act did not revive copyrights that had already expired.
The Act did extend the terms of protection set for works that were already copyrighted, and is retroactive in that sense. However, works created before January 1, 1978 but not published or registered for copyright until recently are addressed in a special section (17 U.S.C. § 303) and may remain protected until 2047. The Act became Public Law 105-298 on October 27, 1998.http://en.wikipedia.org/wiki/Sonny_Bono_Copyright_Term_Extension