Seth Godin is many things: internet guru, entrepreneur, best-selling author, blogger. In the past, we would have said he "wears of many hats". But in the web 2.0 world, it might be better to say he is a member of many tribes. He is especially adept at sharing ideas--whether his own or those of others. And he says that in today's world of growing social media outlets, tribes--groups of people founded on shared ideas and values--are back. And thanks to the growth of tribes, the age of mass marketing, he says, is dead. Here is Godin speaking about leadership and tribes in a TED Talk :