Early in the book he contrasts Columbus' trip west from Europe to discover India which served to prove that the Earth is round to his trip east from the US to India where he discovered that the world is flat. He is talking about globalization of course; he researched and wrote about the various political, technological, social, and economic factors and their interactions that have enabled so many changes in the last 20 years. Thus far it's been extremely interesting reading - I'm only a third of the way through the book.
Chapter two is where he describes in great detail the 10 forces that flattened the world. Number one is 11/9/89 - the fall of the Berlin Wall; number two is 8/9/95 - Netscape going public; number three is Work Flow software; and number four is Open Source software.