Ontology versus Stigmergy
ontology deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and differences.
By contrast stigmergy is a consensus social network mechanism of indirect coordination, through the environment, between agents or actions. The principle is that the trace left in the environment by an action stimulates the performance of a next action, by the same or a different agent. wikipedia
Different forms of internet representation and tooling express a different balance between these two factors.
A digital-garden per se tends towards an ontological representation - the concepts expressed, and the links established between the concepts are the emergent view of the author.
However as these are just one more form of internet publishing, in so far as an author is influenced by the writings of others then a Stigmergic principle can be seen at work.