Link and Triadic Closure Delay: Temporal Metrics for Social Network Dynamics
Matteo Zignani
Sabrina Gaito
Gian Paolo Rossi
Xiaohan Zhao
Haitao Zheng
Ben Y. Zhao
Proceedings of 8th AAAI International Conference on Weblogs and Social Media (ICWSM 2014)
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Paper Abstract
Today, numerous models and metrics are available to capture and characterize
static properties of online social networks. When it comes to understanding
their dynamics and evolution, however, research offers little in terms of
metrics or models. Current metrics are limited to logical time clocks, and
unable to capture interactions with external factors that rely on physical
time clocks. In this paper, our goal is to take initial steps towards building
a set of metrics for characterizing social network dynamics based on physical
time. We focus our attention on two metrics that capture the "eagerness" of
users in building social structure. More specifically, we propose metrics of
link delay and triadic closure delay, two metrics that capture the time delay
between when a link or triadic closure is possible, and when they actually
instantiate in the trace. Considered over time or across traces, the value of
these metrics can provide insight on the speed at which users act in building
and extending their social neighborhoods. We apply these metrics to two real
traces of social network dynamics from the Renren and Facebook networks. We
show that these metrics are generally consistent across networks, but their
differences reveal interesting properties of each system. We argue that they
can be attributed to factors such as network maturity, environmental and
social contexts, and services offered by network provider, all factors
independent of the network topology and captured by our proposed metrics.
Finally, we find that triadic closure delays capture the ease of neighbor
discovery in social networks, and can be strongly influenced by friend
recommendation systems.