Opinion of the Court
for acts of copyright infringement by third parties using the product. We hold that one who distributes a device with the object of promoting its use to infringe copyright, as shown by clear expression or other affirmative steps taken to foster infringement, is liable for the resulting acts of infringement by third parties.
I
A
Respondents, Grokster, Ltd., and StreamCast Networks, Inc., defendants in the trial court, distribute free software products that allow computer users to share electronic files through peer-to-peer networks, so called because users’ computers communicate directly with each other, not through
neys by Kevin P. Roddy and Matthew E. Van Tine; for Sixty Intellectual Property and Technology Law Professors et al. by Deirdre K. Mulligan and Pamela Samuelson; for Sovereign Artists et al. by James R. Wheaton; for Computer Science Professor Harold Abelson et al. by James S. Tyre; for Professor Edward Lee et al. by Mr. Lee, pro se; for Charles Nesson by Mr. Nesson, pro se; and for Malla Pollack et al. by Ms. Pollack, pro se. Briefs of amici curiae were filed for the American Intellectual Property Law Association by Rick D. Nydegger and Melvin C. Garner; for Audible Magic Corp. et al. by Bruce V. Spiva and Jeremy H. Stern; for Bridgemar Services, Ltd. d/b/a iMesh.com by Jeffrey A. Kimmel; for the Business Software Alliance by E. Edward Bruce and Robert A. Long, Jr.; for Creative Commons by Lawrence Lessig; for the Digital Media Association et al. by Lawrence Robbins, Alan Untereiner, Markham C. Erickson, and Jerry Berman; for Emerging Technology Companies by Michael Traynor and Matthew D. Brown; for IEEE USA by Matthew J. Conigliaro, Andrew C. Greenberg, Joseph H. Lang, Jr., and Daniel E. Fisher; for Innovation Scholars and Economists by Laurence F. Pulgram; for the Intellectual Property Owners Association by James H. Pooley; for Media Studies Professors by Roy I. Liebman; for the National Venture Capital Association by Michael K. Kellogg, Mark L. Evans, and David L. Schwarz; for Sharman Networks Limited by Mr. Dorman; for SNOCAP, Inc., by Joel W. Nomkin; for Kenneth J. Arrow et al. by David A. Strauss; for Lee A. Hollaar by Lloyd W. Sadler; for U. S. Senator Patrick Leahy et al. by Mr. Leahy, pro se, and Senator Orrin G. Hatch, pro se; and for Felix Oberholzer-Gee et al. by Carl H. Settlemyer III and Arnold P. Lutzker.
