It's always important to know exactly what U.S. copyright law says about downloading music, even though it's not complicated. The law says that it's illegal to download any music that's been duplicated or distributed without permission. Downloading music from a site that provides the music free and without statement of copyright should give you a clue that what you're doing is illegal. Despite that, many people download illegally anyway, thinking they won't get caught. Others may be new to downloading music and do not realize that the file-sharing site they're using is breaking the law.
The U.S. Supreme Court and lower courts have ruled repeatedly in favor of the Recording Industry Association of America who continuously battle illegal downloads. While the RIAA continues the fight, courts make it clear that downloading music illegally will be fully prosecutable. Many of these cases are built on the Supreme Court ruling from 2005, otherwise known as the MGM v. Grokster case.
If you get caught illegally downloading music, either on purpose or unknowingly, you could face some very serious prison time and fines from both criminal and civil court. In a criminal court, a first-time offense can send you to prison for five years and a $250,000 fine. For civil cases, being sued could cost you nearly the same as the criminal fine. Generally, a civil penalty is $750 for every song downloaded illegally. There's also a national law called the No Electronic Theft Law, or NET, that imposes the same fines and prison time from the courts. It expands, though, to include downloading from P2P file-sharing networks that store and share music on your hard drive. If you do that, you could face up to five years in prison. Also under this law, copyright holders can sue you for statutory damages.
Those who purposely illegally download music know how to avoid it. But for those not aware, you need to know a few things that might surprise you. One way to know if you're downloading illegally is by checking your email to see if someone gave you a link to a downloadable song. In many cases, these are taken illegally, and you'll be breaking the law if you download it or share it with others. The same applies if you make an MP3 file from a CD and then share it on the net through file-sharing networks. Transferring copyright music through instant messaging systems is also illegal as well as burning illegally-downloaded MP3s to multiple CDs that you then pass around to all your friends for free.
Be sure to check the file-sharing network you're using and make sure they note all the music is copyrighted. It should state copyright at the bottom of the site's main page or near the title of each song you're downloading.