The Digital Millennium Copyright Act (DMCA) contains two main sections that have been a source of particular controversy since they went into effect in 2000. The "anti-circumvention" provisions (sections 1201 et seq. of the Copyright Act) bar circumvention of access controls and technical protection measures. The "safe harbor" provisions (section 512) protect service providers who meet certain conditions from monetary damages for the infringing activities of their users and other third parties on the net.

In enacting the "anti-circumvention" provisions of the DMCA Congress ostensibly intended to stop copyright pirates from defeating DRM and other content access or copy restrictions on copyrighted works and to ban the "black box" devices intended for that purpose. In practice the DMCA anti-circumvention provisions have done little to stop "Internet piracy." Yet the DMCA has become a serious threat that jeopardizes fair use impedes competition and innovation chills free expression and scientific research and interferes with computer intrusion laws. If you circumvent DRM locks for noninfringing fair uses or create the tools to do so you might be on the receiving end of a lawsuit.

The DMCA “safe harbors” protect service providers from monetary liability based on the allegedly infringing activities of third parties. To receive these protections service providers must comply with the conditions set forth in Section 512 including “notice and takedown” procedures that give copyright holders a quick and easy way to disable access to allegedly infringing content. Section 512 also contains provisions allowing users to challenge improper takedowns. Without these protections the risk of potential copyright liability would prevent many online intermediaries from providing services such as hosting and transmitting user-generated content. Thus the safe harbors, while imperfect, have been essential to the growth of the Internet as an engine for innovation and free expression.