Every day, millions of computer users share files online. Peer-to-peer (or P2P) file sharing can give people access to a wealth of information, including music, games and software. Often the files are free and easily accessible.
The risks of file sharing
If you don't enable the proper settings for your computer, you could allow access not just to the files you intend to share, but also to other information on your hard drive, like your tax returns, email messages, medical records, etc.
Alternatively, you may have downloaded or shared material that is protected by copyright laws, which would mean that you could be breaking the law. In some instances, media can be used or shared under the Creative Commons license or for academic purposes. See the MIT Libraries for more information on the dos and don'ts of using copyrighted material.
In addition, files that you download from the Internet could be laden with dangerous code (this type of malware is called a Trojan horse). While you think you might be downloading a piece of software you want, you could unintentionally be downloading a virus as well.
Piracy and copyright infringement
The copyright infringement of media, referred to as piracy, is regulated in most countries by copyright laws. The Digital Millennium Copyright Act (DMCA) was enacted in the United States in 1998 and pertains in particular to copyright of digital material. Proposed laws such as SOPA (Stop Online Piracy Act) and PIPA (Protect Intellectual Property Act) are seeking additional penalties regarding websites where copyrighted material is pirated.