Online communities have increased in size and importance dramatically over the last decade. The fact that many communities are online means that it is possible to extract information about these communities and the connections between their members much more easily using software tools, despite their potentially very large size. The links between members of the community can be presented visually and often this can make patterns in the structure of sub-communities immediately obvious. The links and structures of layered communities can also be formalized to gain a better understanding of their modelling. This paper explores these links with some specific examples, including visualization of these relationships and a formalized model of communities using the Z notation. It also considers the development of such communities within the Community of Practice social science framework. Such approaches may be applicable for communities associated with cybersecurity and could be combined for a better understanding of their development.