Complexity and Social Networks

Do you know that anyone on earth can be connected to any other person through a chain of acquaintances that has no more than five intermediaries ? (Six degrees of separation theory). Do you know that the size of a genuine social network is limited to about 150 ? (Dunbar Number).
What is the network model of my organization ? What are the emerging patterns and dynamics ? Is my company well adapted to its market ? How can I locate key players ? …
Social network theory views humans relationships as a network of agents connected through various acquaintances. The analysis of these networks is crucial for a better understanding in sociology, anthropology, organizational studies, economy and finance, etc. Within these domains, Internet plays a central role since online social networks (forums, chats, blogs, wikis, online games, etc.) are becoming increasingly popular. We can model such networks of interacting entities using classical approaches in the science of complexity: cellular automata, random networks, multi-agent system, etc. However, it appears to me that a hierarchical modeling could constitute a better approach (more precisely a hierarchy of intricated small-world agent-based networks). Let me try to explain why. First, it seems obvious that only multiple levels can reflect the complexity of real cases. At the lower level there is always a communication medium. For online social networks, this physical network is a graph of connected computers and servers, portable devices, mobile phones, etc. On top of this physical network, there are many possible different levels: individuals but also organizations, companies, countries, nations, etc., and other ones like social, cultural communities or any other forms of communities of interest. My second argument is that "classical" models are simple and universalist, let say: easy to model, to code and to understand. However, even they provide very interesting results in terms of emerging global dynamics and trends, they are generally inadequate for modeling a specific case to obtain practical informations. I think that the study of hierarchical multi-agent systems for modeling (online) social networks represents a promising approach and could contribute to give useful results in many real-world applications.