Have you ever thought about yawning, for instance? Yawning is a surprisingly powerful act. Just because you read the word "yawning" in the previous two sentences — and the two additional "yawns" in this sentence — a good number of you will probably yawn within the next few minutes. Even as I'm writing this, I've yawned twice.

We are all, at heart, gradualists, our expectations set by the steady passage of time. But the world of the Tipping Point is a place where the unexpected becomes expected, where radical change is more than a possibility. It is — contrary to all our expectations — a certainty.

(...) the success of any kind of social epidemic is heavily dependent on the involvement of people with a particular and rare set of social gifts.

In general, people chose friends of similar age and race. But if the friend lived down the hall, then age and race became a lot less important. Proximity overpowered similarity. [...] We're friends with the people we do things with, as much as we are with the people we resemble. We don't seek our friends, in other words. We associate with the people who occupy the same small, physical space that we do.

Six degrees of separation doesn't mean that everyone is linked to everyone else in just six steps. It means that a very small number of people are linked to everyone else in a few steps, and the rest of us are linked to the world through those special few.

My social circle is, in reality, not a circle. It is a pyramid. And at the top of the pyramid is a single person — Jacob — who is responsible for an overwhelming majority of the relationships that constitute my life. Not only is my social circle not a circle, but it's not "mine" either. It belongs to Jacob. It's more like a club that he invited me to join.