David Campbell has a good discussion of file-sharing of digital media at his blog, based on the Copy Culture in the US and Germany study.

Many discussions of these issues proceed in terms of assumptions and generalisations that often have little evidence to back them up. The great virtue of Copy Culture is it provides some hard data on what is actually happening in the new media economy, and that data paints a picture at odds with the oft-heard claims about a rampant and destructive “culture of free” on the web – symbolised in the graphic at the top of this post.

Would be interesting to know if something similar happens with book buying and downloading, and in terms of music whether people make a distinction between work by major artists/labels and work by independent ones.