Limiting Communications

I'm in another of my reading zones and currently I'm reading "Here Comes Everybody - The Power of Organising without Organisations" by Clay Skirky.  I thought this quote from page 42 was interesting and telling: "If you have ever wondered why so much of what workers in large organisations know is shielded from the CEO and vice president, wonder no longer: the idea of limiting communications, so that they flow only from one layer of the hierarchy to the next, was part of the very design of the system at the dawn of managerial culture".