Pop stars angry
Lots of pop stars are really annoyed that their music is being offered for free on websites, because they don't get any money from it.
Madonna's really hacked off with people pinching her music.
Parts of her last album, Music, showed up on websites like Napster before the album was in the shops.
But, someone has tried to get their own back on Madonna's angry message.
For a short while they managed to hack into her official site and offer album tracks for download!