Here Comes Everybody ends and examines how excess free time and the adoption of social media are transforming us from consumers into collaborators.
We've had surplus free time for a while, Shirky contents, at least since the postwar boom. However, because we spent so much of this excess time watching television, the surplus was mostly used for consumption. It has only been in recent years, with the emergence of online social networks, that we're beginning to see our cognitive surplus applied beyond consumption, to all manner of sharing and collaborative creation.
It's worth noting here that the application of our cognitive surplus to social networks is instrumental. It won't by definition produce output of higher quality. You will instead get everything from Wikipedia to Napster to millions of blogs and Twitter posts. But because the Internet has removed the barriers to entry for amateurs creating and sharing content, the pool of content and user cultures is an order of magnitude greater and beyond what it ever was before. This is transformative change, the results of which won't be clear for years, if not decades.
If you liked Here Comes Everybody, you'll probably enjoy Cognitive Surplus too. If you haven't read Here Comes Everybody, I'd suggest you start there first.