We are witnessing the rise of the articulate...

"We are witnessing the rise of the articulate and the marginalization of the inarticulate, whether in our political and business leaders or in our leading brands and most favored Internet sites."

This is saying that people are becoming more well-spoken in various aspects of society, including in politics and business, and on the internet. It's also saying that people that are articulate will be more succesful then thsoe who are not.