The key is the device's ability to become whatever a user needs. Typically, the more a gizmo does, the worse it gets at each separate job. Less is always more. The iPhone, however, is arguably better at everything it does, because it does so much. Start with the App store, which is now packed with more than 25,000 applications. Now add the ability to sell subscriptions that regularly deliver fresh content, additional levels for games or new content, all announced Tuesday. Suddenly an iPhone app can be a digital bookstore, or a digital newspaper, or a game that doles out fresh content by the slice. More is more.
