This book had some great information packed inside of a repetitive package that wasn't very sticky.

Once you picked up the key ideas, most of the conclusions followed in a fairly obvious manner. The key ideas or, at least, the ones that I remember, were:
- Network influence tends to travel three degrees before shrinking to statistical insignificance. You influence your friends, friends' friends, and friends' friends' friends, and they influence you back. The strength of influence decreases with each separation, but the number of people influenced increases.
- Network effects are real. They persist even once researchers account for other sources of similarity in the network such as homophily (the tendency for like to be connected to like) and common external factors (people near each other in the network may share experiences).
Everything travels across the network -- ideas, emotional state, behavior, disease, etc. -- and because of the three degrees of influence rule, you only have limited control over what you are exposed to and who you can influence.
- Not all network ties are equal (weak ties and strong ties). The most important information tends to come from ties that are distant or weak. This is because you have a pretty good idea of the information held by those connected with close, strong ties. For example, people tend to find jobs and relationship opportunities through distant or weak ties because they have generally already evaluated the opportunities presented by their strong, close ties. Distance brings information that you have not already incorporated.

Once you know these principles, much of the rest of the book becomes fairly straightforward.

The authors did present some compelling information in their discussion of the internet. Based on studies that they and others have done, they concluded that relationships on the internet tend to be largely the same as traditional relationships. The mix may have changed (more weak ties, perhaps) and the means of network maintenance have certainly changed, but, for better and worse, people are still largely the same creatures.

Overall, I am glad that I read this book. The information was interesting even if the presentation was less than gripping. The information in the book consisted almost exclusively of real studies, so the conclusions seem well founded, even if not surprising. ( )

Choppy and unengaged. ( )

Overall this is a book worth reading. It provides genuinely interesting insights with potentially far reaching implications for society and arguably for each of us as individuals. In my mind it's worth considering the world through this lens.

The book is made of many examples of studies which show how social networks work, how we influence each other, how ideas are spread, how that links to how diseases are spread and so on.

Some of the conclusions from these studies are in line with what one would expect, but most other small or greater insights into networks that I think most of us wouldn't have considered. One of the primary assertions of the book is that we influence and are influenced by people we don't know (friends of friends). There is a lot of exploration of the importance of networks to human beings, generally we sacrifice some independence to cooperate with others for our protection and well being. Also challenged is the traditional economist view of self-interest as opposed to altruism. The point being, again, that we value relationships with others beyond what is economically in our interests. The idea that we give to others purely in the anticipation of a favour returned is challenged as not representing the whole picture of what motivates us.

The weakness of the book is mainly its structure. The series of ideas and the studies that support them feel more like a collections of themed thoughts than a progressive series of arguments and evidence that lead to an undeniable conclusion. That said, still an interesting read. ( )

A nice overview of research on social networks and how they affect the patterns and dynamics of the distribution of a huge variety of things, such as infectious disease, smoking and voting practices. It also looks at the effects of technology (particularly email and social-networking sites) on our networks. It's pretty light on the maths but explains core concepts clearly and with a lot of diagrams, and has a ton of citations to papers, books and newspaper articles should you wish to dig deeper into any of the topics covered. ( )

very statistical, acturial and for the most part boring.