In the following video, Motley Fool contributor John Reeves takes a closer look at Apple's (AAPL 1.77%) fastest-growing business. The segment is iTunes/Software/Services, and it grew 25% year on year in the most recent quarter. Apple's management believes that its content is the very best in the industry. Consumers clearly love the content and are buying more of it. They're also buying the devices that deliver the content. John is very encouraged by the long-term trend.