Here's an article from the National Geographic magazine that provides a low impact introduction to swarm theory.
In essence, it provides readers with insight into how small autonomous entities (in our case guerrilla groups with a diverse set primary loyalties and thereby a similarly diverse set of motivations for why they fight), armed with simple rules of behavior (the rules of open source warfare), can coordinate (via stigmergic signaling) their actions to produce intelligent behavior at the aggregate level (an emergent intelligence sufficient to fight a war at the operational and strategic levels).NOTE: Swarm theory also informs us on the potential effectiveness of unsupported organic terrorists in the West. Without an open source network in residence, the organic terrorist in the developed West is much more likely to fail than not (very much like a small group of bees/ants disconnected from the swarm -- lost and confused). However, improvements in virtual environments that provide new sources of connectivity are starting to unlock this potential -- although this type of development usually takes longer to develop than most people suspect. It may take a decade for the ratio to shift to where there are more successes than failures.