Works of authorship originate in private, safely kept under common law protections. Once published, however, expressive works become data ferae naturae—wild and natural information. As such, expressive works roam and reproduce freely. They may get captured in fixed copies, caged in atoms or bits. But the public, once it has absorbed an expressive work, generally retains relatively cheap access to it—unless and until copyright intervenes.
Copyright law limits public access to expressive works, herding them off the commons and into private hands. The Copyright Act offers a sort of ranch to authors, giving them a place to birth, raise, and sell their expressive works safe from the deprivations of grasping strangers. Authors enjoy those special privileges against the public not as a natural right, but rather solely thanks to a policy authorized by the U.S. Constitution and implemented through the Copyright Act. [The figure below] illustrates the path that copyright, together with some of its legal next-of-kin, takes from its origins towards its goals.
The Technology Liberation Front is the tech policy blog dedicated to keeping politicians' hands off the 'net and everything else related to technology.