There are very fundamental reasons we live our lives in social networks and if we really understood the role they're playing in our society we would take better care of social networks and find ways to take advantage of their power to improve our society.

The reason we form networks is because the benefits of a connected life outweigh the costs. It's to our advantage as individuals and a species to assemble ourselves in this fashion.

It used to be thought that our genes were historically immutable and that it was not possible to imagine a conversation between culture and genetics.

We discovered that if your friend's friend's friend gained weight, you gained weight. We discovered that if your friend's friend's friend stopped smoking, you stopped smoking. And we discovered that if your friend's friend's friend became happy, you became happy.

People have just assumed that... if we call our Facebook acquaintances our friends, we must be influenced by them, too. But we're not.

It's fashionable to speak about vulnerable populations in medicine and public policy, but it's harder to find a more vulnerable population than those who are dying.

Social networks are these intricate things of beauty, and they're so elaborate and so complex and so ubiquitous that one has to ask what purpose they serve.