  The different approaches developed to analyze the structure of complex
networks have generated a large number of studies. In the field of social
networks at least, studies mainly address the detection and analysis of
communities. In this paper, we challenge these approaches and focus on nodes
that have meaningful local interactions able to identify the internal
organization of communities or the way communities are assembled. We propose an
algorithm, ItRich, to identify this type of nodes, based on the decomposition
of a graph into successive, less and less dense, layers. Our method is tested
on synthetic and real data sets and meshes well with other methods such as
community detection or k-core decomposition.
