I would say that the average person that commits online piracy does it because they honestly do not look at it as stealing. They do not seem to see a digital file the same way they see a physical DVD or CD. The same guy that excepts a pirated song from his friend would not go into Wal-mart and shoplift the same music in CD form. Using that analogy, I suppose a person could point out that it is the fear of being caught that keeps more people from shoplifting.

Also, there are those that see online piracy as a victimless crime. They point out that producers, directors, musicians and actors make large amounts of money. However, the RIAA claims that piracy is responsible for 71,060 lost jobs in the United States.

Hi @WarrenT!

I read this article online about the reasons why people share files. These are the common reasons why they do this:

1. People share files because they can. This is a simple fact of life that explains everything, this implies that there's no rationale behind file-sharing. People have no arguments or excuse to justify whey they downloaded the music files. They found it there and so they wanted it.
2. People don't care. There are many fans of music that said that they don't care about paying artists. But according to Nick Bilton that it is not because people don't care but they are oblivious to the fact that a human being is on the other side of the digital information that they are consuming.
3. People want to save money and keep their money so they chose to download free files of music. One theory behind this is that file-sharing came at a time when many fans were looking to spend money to pay off their debts instead of spending it buying files.

Source:
http://www.musicthinktank.com/blog/the-real-and-only-reasons-why-fans-file-share-music.html