  Complex networks emerge under different conditions through simple rules of
growth and evolution. Such rules are typically local when dealing with
biological systems and most social webs. An important deviation from such
scenario is provided by communities of agents engaged in technology
development, such as open source (OS) communities. Here we analyze their
network structure, showing that it defines a complex weighted network with
scaling laws at different levels, as measured by looking at e-mail exchanges.
We also present a simple model of network growth involving non-local rules
based on betweenness centrality. The model outcomes fit very well the observed
scaling laws, suggesting that the overall goals of the community and the
underlying hierarchical organization play a key role is shaping its dynamics.
