I know Seth Godin from my MBA classes, "permission marketing" is his terminalogy originally.
This is something to be very careful, a great disease growing and surrounding us each day. Studying something nearly equals to a google search nowadays..
But how can you be sure if they are telling the truth?
Never forget the "Question Authority" and "The differences between a marketing mindset and a scientific mindset" concepts.
This is my email signature, please take it as an advice; "Never believe all you read or hear! Just because it is printed or someone is more experienced doesn't mean it is TRUE.."