I love my iPod. I cannot lie. And I have spent, oh, a very very lot of money in the iTunes store buying music all locked up so that even though I own it, I don't own it, because unlike all the songs off my CDs (that I also bought and own), you can't play your iTunes music on anything other than your iPod.
Welcome to the age of Digital Rights Management, or DMR.
So if you shellac a one-atom-thick layer of DRM over a product, you get the full power of the American legal system as a weapon to use against competitors. Apple may have created a successful "Switch" campaign by reverse-engineering Microsoft products like PowerPoint to make Keynote, an Apple program that lets you run old PowerPoint decks on your Mac, but Microsoft can't create a "Switch to the Zune" campaign that offers you the ability to play your iTunes Store songs on a Zune, Microsoft's latest abortive iPod-killer.
Although Apple's DRM is wholly ineffective at preventing copying, it does manage to raise the cost of switching from an iPod to a competing device. Every iTunes song you buy for 99 cents amounts to a 99 cent tax on switching from an iPod to a Zune. That's because your iTunes songs won't play on your Zune -- or on any other player, save those made or licensed by Apple. Jobs tries to skate around this in his memo, suggesting that only a tiny fraction of the music on iPods comes from his music store, and so the anti-switching effects are minimal.
The rest of this is at Salon - if you're not a subscriber, you can get a free day pass to read the article. It's worth the trouble.