We fight with users here every day to delete copyright material.
Some are not aware, that they have uploaded a file which is protected by copyright laws and especially young people obviously just do not care. They literally grew up with Kazaa and Napster with free CD Rippers and friends, who hand over the latest blockbuster movie on CD in school. I personally guess, that the figure of copyright infringements on the net is in the billions. Graphics, sounds, music, movies and texts are copied, reworked and republished without any sufficient control mechanism: That is IMHO a big problem for the artists and the publishers alike.
In the opinion of Joost and Marieke, there can be a world without copyright.
In my opinion, that world is far away. We deal with around 2-3 complaints every day from people who find their copyrighted software, music, etc. on some users tradebit space. We have to delete these users immediately.
Music, sound and other digital goods are sometimes really big business (think of ringtones, eg) and - right now, right today - we live in a world with rules. Just because you CAN go into the supermarket and secretly eat a bar of chocolate in that sweets department, it does not mean you are ALLOWED to, nor does it mean that this law is faulty just because you could.
Copyright and the business around that is real and for us as a file hoster a very serious topic, which needs a day to day attention with a constant learning curve.