I agree with Jefferson and Tristanrobin. "Sharing" music files over the internet is stealing. It is not sharing. Real sharing is loaning someone your purchased copy of a recording and then getting it back. Real sharing is playing your purchased copy of a recording for someone who is in the same room as you. The musicians and songwriters put effort into their creations, and we as consumers should put in some effort of our own (read that as earning money) to purchase a copy of their work.

It matters not how much money the musicians make. Making copies of their work without their permission is wrong. If the musicians and songwriters want to share, then they should put their work online for that purpose and label it as such. Otherwise, it's stealing, no matter how popular the activity is.