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.

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.

One reason citizens, politicians and university donors sometimes lack confidence in the social sciences is that social scientists too often miss the chance to declare victory and move on to new frontiers.

I like to have met someone in real life before being their Facebook friend.

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

If your friends are obese, your risk of obesity is 45 percent higher. ... If your friend's friends are obese, your risk of obesity is 25 percent higher. ... If your friend's friend's friend, someone you probably don't even know, is obese, your risk of obesity is 10 percent higher. It's only when you get to your friend's friend's friend's friends that there's no longer a relationship between that person's body size and your own body size.

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.