What is stigmergy?
Stigmergy was originally discovered and named about fifty years ago by Pierre-Paul Grasse, a biologist studying ants and termites. He was intrigued to learn how these virtually brainless creatures could create highly sophisticated messaging systems and build extremely complex architectural structures. It was a mystifying puzzle that nobody had ever been able to explain.
What he uncovered defied rational explanation. There were no plans, organization or control built into the brains or genes of the ants. The ants weren't even communicating with each other. The sophisticated frameworks and complex structures were emerging spontaneously. The understanding eventually came about through knowledge gained in the study of the self-organizing characteristics of complex systems.
Complexity arises in stigmergic systems because individuals interact not with each other but with a common environment. They interact with the environment by making changes to it. These changes affect the the way further changes are made. This gives rise to a positive feedback effect, where information feeds upon information (much the same effect as when conversations can take unpredictable directions according to the way people respond to each other's comments).
It has only recently been recognized that this concept provides the explanation as to how and why the Internet and the World Wide Web have self-organized to become increasingly more complex.
Understanding how self-organization and evolution make stigmergy work for ants, allows us to develop highly efficient information sharing systems for niche subject areas.
(See Explaining with an example).