Although the concept of milieu does not necessarily include a spatial dimension, I argue that in the case of information technology industries, at least in this century, spatial proximity is a necessary material condition for the existence of such milieux because of the nature of the interaction in the innovation process. What defines the specificity of a milieu of innovation is its capacity to generate synergy; that is, the added value resulting not from the cumulative effect of the elements present in the milieu but from their interaction. Milieux of innovation are the fundamental sources of innovation and of generation of value added in the process of industrial production in the information age.
