Gladwell is successful because he relays a great anecdote. Anecdotes lend themselves well to re-telling, thus his books are popularised by word of mouth. "Man, I read this great piece by this guy called Gladwell about a policeman who could ready body language so well he held fire when facing off a kid with a gun."

And isn't that precisely the scenario outlined in Tipping point? That's pretty cool - a book that proves its own point. It also reminds me of people who get rich selling self help books.

Is there really a question whether there is something between 4 & 6?