One of my big questions at the moment is how to distinguish between different types and levels of knowledge in a useful manner. 'Knowledge sharing' is such a container word. The distinction between explicit and tacit knowledge is already useful, as I find the distinction between single/double loop learning introduced by Chris Argyris, but I still think we need more subtleties.
One day in the taxi, my daughter was talking about her new class in school, but I did not understand what she meant, so I asked her to explain again. Then she got annoyed and replied: 'Mom, you don't understand, so I don't want to explain to you'. I think this is an example pointing to a fundamental interpersonal process which determines the depth of knowledge sharing between two people: it is only when you feel that people understand you, that you are invited to share more. I believe it is not a matter of trusting or not trusting, but a matter of having the feeling that someone understand the issues you are grappling with.
Hence, communities of practice with more homogenous groups of practitioners may find it easier to connect, albeit the danger of not stimulating enough innovation. And it stresses the importance to create space for people to connect on a one-to-one basis as well.