This essay explores the controversy over peer-to-peer (p2p) software, examining the legal and ethical dimensions of allowing software companies to develop p2p technologies. It argues that, under the Supreme Court’s ruling in the Sony betamax case, technology developers must be accorded the freedom to innovate and develop technologies that are capable of substantial noninfringing uses. This doctrine, known as the Sony doctrine, provides an important safe harbor for technological development, including p2p. The safe harbor, however, does not immunize conduct beyond (...) the design, sale, or supply of the product. For other conduct that falls outside the Sony safe harbor, the traditional standards of secondary liability apply. (shrink)