As I show in Internet Architecture and Innovation, the Internet’s original architecture had two components that jointly created an economic environment that fostered application innovation:
1. A network that was able to support a wide variety of current and future applications (in particular, a network that did not need to be changed to allow a new application to run) and that did not allow network providers to discriminate among applications or classes of applications. As I show in the book, using the broad version of the end-to-end arguments (i.e., the design principle that was used to create the Internet’s original architecture)  to design the architecture of a network creates a network with these characteristics.
2. A sufficient number of general-purpose end hosts  that allowed their users to install and run any application they like.
Both are essential components of the architecture that has allowed the Internet to be what Zittrain calls “generative” – “to produce unanticipated change through unfiltered contributions from broad and varied audiences.”
Stanford professor Barbara van Schewick has written a blog post (as part of a series on Concurring Opinions inspired by Jonathan Zittrain’s book ‘The Future of the Internet and How to Stop It’) on the distinctions between devices and networks in considering the openness of the Internet. [Professor Zittrain’s concept of ‘generativity’ identifies one of the key aspects of what any Internet policy advocate cares about when talking about ‘open’ - the ability of the Internet to encourage innovation and new uses, by everyone, not just the network operators.] These distinctions are particularly salient in the mobile world, because that’s where we’re seeing the rush of closed devices that concerns JZ - the iPad and the iPhone are brand new worlds of consumer-friendly yet largely non-generative consumption platforms.
Professor van Schewick’s post serves as a reminder to the iPad-obsessed crowd that we need an open and generative network, and we’re in real danger of losing the one we’ve got, especially in wireless. We can’t afford to let wireless slip by the wayside of open network policy, and we can’t afford to let 4G networks be built around prioritized IMS channels for certain preferred Internet traffic.