This document discusses social networks and social network analysis. It begins by defining a network as a set of nodes connected by communication for information exchange. It then defines a social network as the social structure between individuals or organizations through social connections ranging from casual to close. The document outlines some popular social networking sites and discusses both the benefits and risks of social networks. It acknowledges that while social networks can help people connect and share interests, they also pose privacy and security risks if personal information is shared. In the end, it concludes that social networks can be good for society if proper precautions are taken, but individuals must make their own choice about participating based on their judgment and experiences.