You gotta love a book with the title, The Cluetrain Manifesto: The End of Business as Usual and whose website begins people of earth... in several terrestrial languages. I haven't read the book yet, but checking out the Amazon review and the website, I definitely have to check it out. The writers take the view that mass communications is transitioning from the model of a few corporations controlling most channels to communications via Web sites and message boards, and in e-mail and chat rooms.
I think their point of view dovetails nicely with the message of The Long Tail (see below). Although most people think the majority of mass communication are through big boys* [General Electric, Time Warner, Walt Disney, Viacom and Rupert Murdock's News Corporation], the amount of intercommunication between people through the other avenues actually exceeds what these companies can spew out.
*Source: National Organization for Women Foundation Digital TV Project: Who Controls the Media