@richard hey have you tried https://roamresearch.com/ ?
@sfyire I've not seen this before. It looks interesting. I've tried https://webbrain.com/ and I keep meaning to try https://kungsgeten.github.io/org-brain.html - I think an open source mark up should be good to use as it's shareable, plus org-mode is incredibly powerful.
ah, I discovered in roam you can do [[my example]] to setup a bi-directional relationship between pages (it will create the page if it doesn't already exist), looks like under the hood it's some kind of datalog thing so you can put a query like :q [:find ?e ?a ?v :where [?e ?a ?v]] in your document and it works https://i.imgur.com/vx4KvNk.png