The iPod made music mobile, but today, how many devices do you need to walk around with? You want it on just one. And inevitably that's going to be the phone.

By packaging a full album into a bundle of music with ringtones, videos and other combinations and variations, we found products that consumers demonstrably valued and were willing to purchase at premium prices. And guess what? We've sold tons of them.

You need to look no further than Apple's iPhone to see how fast brilliantly written software presented on a beautifully designed device with a spectacular user interface will throw all the accepted notions about pricing, billing platforms and brand loyalty right out the window.

Frankly, right is right and wrong is wrong, particularly when a parent is talking to a child. A bright line around moral responsibility is very important.

As my other obligations are beginning to take an inordinate amount of time, I have asked to step down as WMG's board chairman, effective January 31, 2012. However, I will remain a director of the company and in that way, continue my association with Warner Music and its extraordinary people.

If you look at the market cap increase in Apple since it created the iPod versus what's happened to the music industry, you have to say Apple got the better part of that deal.

It's interesting that the book publishing industry, on the iPad, has much more flexibility than the music industry had.