Scale-free, small-world model for network communication

Recently, the small world network model has been popular to describe human social relations and networks formed by biological entities such as neurons. The network model achieves small diameter with relatively few links as measured by the ratio of clustering coefficient and the number of links. It is quite natural to consider email communication as similar to social network pattern. Quite surprisingly we find from our empirical study that email network follows a different type of network model that falls into the category of scale-free network. We propose new network models to describe such communication topology.