The Digital Millennium Copyright Act (DMCA) is a United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization (WIPO). It criminalizes production and dissemination of technology, devices, or services intended to circumvent measures (commonly known as digital rights management or DRM) that control access to copyrighted works. It also criminalizes the act of circumventing an access control, whether or not there is actual infringement of copyright itself. In addition, the DMCA heightens the penalties for copyright infringement on the Internet.Passed on October 12, 1998, by a unanimous vote in the United States Senate and signed into law by President Bill Clinton on October 28, 1998, the DMCA amended Title 17 of the United States Code to extend the reach of copyright, while limiting the liability of the providers of on-line services for copyright infringement by their users.
The DMCA's principal innovation in the field of copyright is the exemption from direct and indirect liability of internet service providers and other intermediaries. This exemption was adopted by the European Union in the Electronic Commerce Directive 2000. The Copyright Directive 2001 implemented the 1996 WIPO Copyright Treaty in the EU.
For more detailed information see: http://en.wikipedia.org/wiki/Digital_Millennium_Copyright_Act