With the popularity of Facebook, Twitter, LinkedIn, and other social networks, we're increasingly defined by who we know and who's in our network. These websites help us manage who we know—whether personally, professionally, or in some other way—and our interactions with those groups and individuals. In exchange, we tell these sites who we are in the network.

These companies, and many others, spend a lot of time on and pay attention to our social networks. What do they say about us, and how can we sell things to these groups?

In this chapter, we'll walk through learning about and analyzing social networks: