iTunes is a closed marketplace. If you want to sell stuff, you have to give it to Apple. Thankfully for them, their iPod is pretty ubiquitous (despite breaking frequently and having lousy sound quality), so they can do what Microsoft have been doing for years by building a 'closed' system for content delivery. The AAC format used for their audio files does not translate well to other environments and it is a (successful) exercise in empire building.
Now, those of you who know me will know that Steve Jobs is my all time business hero, but I seem to recall a time in the later eighties when he refused to licence the Mac OS for use on other computers, and when his successor did, it was too late.
Is it another case of the tortoise and the hare, or will iTunes open its walled garden ?