Ideas of connected ideas
Commonplace book, Memex, Hypertext, Hypercard, Zettelkasten, Wiki, … They all share the same idea: we want to have a central place to store ideas (External brain) where we can store lots of information and make connection between ideas and information. The ability to make association is critical for making information discoverable and nudging new thoughts (combinations of ideas).
What are the tools? Obsidian is a nice option for handling locally stored connected Markdown files.
YYiki is a minimal app for serving connected Markdown files as a Wiki.