The average person who does not download music spends £44 ($72) a year on CD's, while people who do pirate music spend about £77 ($126) a year on CD's.
http://news.bbc.co.uk/2/hi/technology/8337887.stm
If this is the case, should companies support file-sharing? I think so. It's like movie studios who put their videos in tape stores or on TV, or artists who put their music on the radio. If you let people sample a product, they are more likely to buy it in the future.