When a book is published, it is one source producing static information for many readers. One to many. Producer -> Consumer(s). To create a book before the internet you had to be in the central location of the working copy. For more detailed historical analysis of how the printing press created highly centralized societies, check out The Gutenberg Galaxy by Marshall McLuhan.
On the contrary, with the internet, many people are producing and consuming dynamic content simultaneously with many people who are doing the same. Many to many. Prosumer <-> Prosumer. Think of a Google Doc where anyone located anywhere across the globe can simultaneously collaborate on a Google Doc.