Style changes emergent to (i.e. not generated within) a subworld involve enterpreneurs who cross-appropriate practices natural in other contexts.
A definition of emergent properties, from Allan & Starr (1982):
Emergent properties (a) Properties which emerge as a coarser-grained level of resolution is used by the observer. (b) Properties which are unexpected by the observer because of his incomplete data set, with regard to the phenomenon at hand. (c) Properties which are, in and of themselves, not derivable from the behavior of the parts a priori.
Innovation can from from the formal or the informal.
This view of innovation, as practice, is counter to the idea of design. Wenger (1998) says that
... practice is not the result of design but rather a response to it.
As a consequence, the challenge of design is not a matter of getting rid of the emergent, but rather of including it and making it an opportunity.
Wenger (1998), p. 233