a) Come up with a great, simple idea
b) Make the site very clean and simple
c) Launch publicly
d) MASSIVE VIRAL GROWTH! (Of course, more modestly ;))
That seems to go against conventional startup wisdom, where you have to fight tooth and nail for a long time before you start getting traction. These interviews of late are really motivating and awesome, but at the same time, they are sort of demoralizing because the subtext seems to indicate that if you aren't growing super fast from day one, you are almost better off just starting over.