Stigmergy is a consensus social network mechanism of indirect coordination, through the environment, between agents or actions….

“Stigmergy is a consensus social network mechanism of indirect coordination, through the environment, between agents or actions. The principle is that the trace left in the environment by an action stimulates the performance of a next action, by the same or a different agent. In that way, subsequent actions tend to reinforce and build on each other, leading to the spontaneous emergence of coherent, apparently systematic activity.”

–Wikipedia (viainthenoosphere)