Here's an interesting post related to the issue of reselling 'used' MP3s. According to the article when it comes to to the reselling of MP3s the recording industry is arguing that a music download is not like a purchase of a CD but is a sale of a license and thus the first sale doctrine does not apply. However, when it comes to compensating the artist the recording industry argues that a music download is like the sale of a CD which has a lower royalty rate than the sale of a license. The industry wants it both ways.