Because communities of practice are loosely knit, they cannot be created by external forces such as management pressure. They can only be supported and nurtured if they are truly essential to the organization.
The good news is that informal communities of practice are almost always present in some form; they simply need to be officially recognized and promoted by the organization to continue thriving. This means:
By selecting which communities to support officially, the organization establishes a two-way feedback loop with such communities.