The primary economic and cultural significance of copyright today comes from works and rights that weren’t contemplated by the Framers of the Constitution’s Copyright Clause. Some, like videogames, were barely considered by the drafters of the 1976 Copyright Act, and new means of distribution have profoundly changed the scope and meaning of copyright even for entrenched genres.1 Performance — both as protected work and as right — is where much of copyright’s expansion has had its greatest impact, as new technologies have made it possible to fix performances in records and films and as cultural change has propelled recorded music and audiovisual works to the forefront of the copyright industries.2
Performance is now the prototype for all works. For one thing, the expansion of copyright beyond exact copying to substantial similarity and derivative works means that the actual scope of a copyright encompasses a practically infinite set of potential variations. This mimics the standard condition of any play or score, which carries with it a practically infinite set of potential performances, all of which will be understandably perform- ances of the underlying work. Yet copyright has never fully conceptual- ized performance, and this has led to persistent confusion about what copyright protects.