Internet technological innovations, particularly the development of Peer-to-Peer ("P2P") networks and the proliferation of user-generated content sites, have introduced considerable challenges for the application of copyright law and infringement liability. The response from the courts and Congress has been mixed, with severe legal curtails being applied to P2P technology while user-generated content sites have been afforded a level of protection against infringement claims as part of the Digital Millennium Copyright Act's section 512 "safe harbor" provisions. However, these provisions have raised concerns about the issue of secondary copyright liability, a matter that has still been left undefined. This Note will argue that the substantial noninfringing use standard enumerated in the case of Sony Corp. of America v. Universal City Studios, Inc. could provide a guide for developing a standard for secondary liability of user-generated content sites.