The tradition in computing has been to avoid duplication for fear that inconsistency would emerge in the presents of change. We prefer to explore and exploit that inconsistency considering it a primary feature of wiki.
Like any cultural construction a wiki lives from the energy given to it by its users. Centralization of resources works against this vitality.
We recognize a tug-of-war between designed control of mechanism (the program) and emergent properties of scale (the system). With the natural world as a guide we create affordances within wiki in support of those processes.