Our survey contains four aspects of understanding
user behavior in OSNs. First, a social
graph is a classic and effective mathematical
model to represent the relationship between
users in OSNs, and has been widely used in OSN
research. Based on four different types of social
graphs, we discuss the aspect of connectivity and
interaction. Second, network monitoring records
detailed traffic activity of OSNs and provides us
with a method to understand the network usage
of OSNs. Also, network-based measurement
results can demonstrate more users’ activities
than using the social graph only. Therefore, we
focus on the perspective of traffic activity. Third,
the rapid development of mobile platforms and
applications plays an important role in OSNrelated
applications.