I'm still trying to wrap my head around this one to understand all of the implications, but even at this point it's clear: The Topology of Covert Conflict, a technical report by Shishir Nagaraja and Ross Anderson of the Cambridge University computer laboratory, is an important piece of research into network-embedded conflicts. As the abstract makes clear, this research has wide application:
Often an attacker tries to disconnect a network by destroying nodes or edges, while the defender counters using various resilience mechanisms. Examples include a music industry body attempting to close down a peer-to-peer file-sharing network; medics attempting to halt the spread of an infectious disease by selective vaccination; and a police agency trying to decapitate a terrorist organisation. [...] Our models thus build a bridge between network analysis and evolutionary game theory, and provide a framework for analysing defence and attack in networks where topology matters. They suggest definitions of efficiency of attack and defence, and may even explain the evolution of insurgent organisations from networks of cells to a more virtual leadership that facilitates operations rather than directing them.
It's a dense article, with useful insights both for those who are working to prevent networked epidemics (of biological or computer viruses) and those who seek to use networked models for social change (such as "second superpower" political movements).
(Via Bruce Schneier)