The Economist on Zune dynamics -- read the full article (no subscription required)
As Microsoft borrows from Apple, the opposite is also true. After failing to defeat Microsoft in operating systems, Apple learned a valuable lesson and has opened up its music technology just enough to make it a standard. It licensed the iPod's connector-plug so that other firms could make accessories for it, and it made the iPod and iTunes available on Windows, something that would once have been unthinkable. The great irony of the epic rivalry between Apple and Microsoft, says Mr Bajarin, is that the longer they fight, the more they resemble each other.