It seems to me that the advent of the Internet marks the dawn of a new era of sharing. I believe the internet enabled the development and proliferation of open source, freely shared software. I believe it has also enabled an explosion of freely available content of all sorts. Interestingly enough, a requirement in this class is to share our thoughts in a blog, which is made freely available throughout the world.
At the core of Internet infrastructure are peering agreements, which are essentially agreements to share freely. The protocols which allow the Internet to function efficiently are for the most part followed voluntarily. Customer provider relationships, which are not about sharing but rather buying and selling, rely on the sharing that exists at the core.
One might argue that the world's academic institutions together with the contributions of scholars throughout recorded history lie at the center of modern civilization. Modern democracies are also at the core of modern society and also are largely based on voluntarism and sharing. Commercial activity in society relies upon the sharing which exists at the core.
As we study the technical innards of the Internet, it is apparent to me how much voluntary cooperation is relied upon for everything to work well together. It is a little surprising, and very interesting for me to think about. It helps me to appreciate others more and the contributions they have and are making to my quality of life.