The introduction of the MP3 format catalyzed the act of downloading music from the Internet. MP3 is a MPEG standard used for the compression of audio signals into very small computer files, and especially for transmitting music digitally over the Internet. This compression has radically minimized the time take to download such music files and along with the relatively small size of these files, hundred even thousands can be stored on a computer without filling the hard drive. A continually evolving technological society has also lead to the development of portable devices with the ability to store and play MP3 files. Such devices include; the Apple iPod, the MP3 Player and the mobile phone.
How music is played and in which device it is played on is generally not of an issue, but significant issues can arise with regard to the source of the music files and how they are used. Downloading music files from licensed sites, like iTunes is completely legal. However, the act of exchanging and sharing music files over the Internet is completely against the law. It usually occurs through un-licensed, file sharing sites over the Internet (such a LimeWire), and is also know as P2P or peer-to-peer file sharing. Early forms of P2P sites (Grokster, for example) stored all files in a central place called a server and required users to access the server to browse through the files. Grokster followed this same design principle. Following a High Court decision in June of 2005, Grokster was found directly responsible for allowing illegal use and was shut down on the 7 of November 2005. More recent sites, such as LimeWire, however are not as easily held accountable. Due to it sever Grokster could be held liable for directly contributing to the breach of copyrighted work.