Zettelkasten (German for "slip box") is a note-taking method popular amongst some LWers, and often praised for its scalability.
A clear explanation of how this works can be found at abramdemski's post: https://www.lesswrong.com/posts/NfdHG6oHBJ8Qxc26s/the-zettelkasten-method-1