that is the question posed in this article over at Fast Company which discusses hte work of Duncan Watts who refutes Malcolm Gladwell’s “tipping point” theories. from the article:

In the past few years, [Duncan] Watts–a network-theory scientist who recently took a sabbatical from Columbia University and is now working for Yahoo –has performed a series of controversial, barn-burning experiments challenging the whole Influentials thesis. He has analyzed email patterns and found that highly connected people are not, in fact, crucial social hubs. He has written computer models of rumor spreading and found that your average slob is just as likely as a well-connected person to start a huge new trend. And last year, Watts demonstrated that even the breakout success of a hot new pop band might be nearly random. Any attempt to engineer success through Influentials, he argues, is almost certainly doomed to failure.