Online social networks have already become a bridge connecting our physical daily life with the
(web-based) information space. This connection produces a huge volume of data not only about
the information itself but also about user behavior. The ubiquity of the social Web and the
wealth of social data offer us unprecedented opportunities for studying the interaction
patterns among users so as to understand the dynamic mechanisms underlying different networks
something that was previously difficult to explore due to the lack of available data.In this
book we present the architecture of the research for social network mining from a microscopic
point of view. We focus on investigating several key issues in social networks. Specifically
we begin with analytics of social interactions between users. The first kinds of questions we
try to answer are: What are the fundamental factors that form the different categories of
social ties? How have reciprocal relationships been developed from parasocial relationships?
How do connected users further form groups?Another theme addressed in this book is the study of
social influence. Social influence occurs when one's opinions emotions or behaviors are
affected by others intentionally or unintentionally. Considerable research has been conducted
to verify the existence of social influence in various networks. However few literature
studies address how to quantify the strength of influence between users from different aspects.
In Chapter 4 and in [138] we have studied how to model and predict user behaviors. One
fundamental problem is distinguishing the effects of different social factors such as social
influence homophily and individual's characteristics. We introduce a probabilistic model to
address this problem.Finally we use an academic social network ArnetMiner as an example to
demonstrate how we apply the introduced technologies for mining real social networks. In this
system we try to mine knowledge from both the informative (publication) network and the social
(collaboration) network and to understand the interaction mechanisms between the two networks.
The system has been in operation since 2006 and has already attracted millions of users from
more than 220 countries regions.
