In Ahrens’ book How to Take Smart Note, the author categorised notes into five types. I agree with most of it but wanted to tweak it to suit me better. After all, note-taking is a very personal thing.
Capture: fleeting notes
Your scrawls on serviettes, brown bags, or coffee shop receipts. They are random ideas you jolted down while reading, waiting, waiting in a queue, or talking with a friend. You write down your experiences, what you have done, how you achieved it, the light bulb moments, or the mere inferences you drew from your gut feelings.
Process them within a day or two while the memory is still fresh. You can bin these after you’ve turned them into permanent notes.
Process: permanent notes
Notes that represent atomic ideas which can be understood in their own contexts.
The title of the Zettel should be descriptive. The first sentence or paragraph should be the summary of the idea.
Process: connection notes
Notes that connect related ideas. The focus of these notes are the relationships between the atomic concepts.
If combining two or multiple concepts sparks new insights, create a new note for the connection alongside the insights.
Reading: literature notes
Summarise the content of a book, a publication, a podcast or a blog post and give the citation in the format of “on page X of Y, it says Z”. You can keep a separate bibliography slip-box with tools such as Zotero or org-ref.
Organisation: project notes
Notes that serve as ‘folders’ or ‘tags’ for specific projects. You can archive them or bin them once the projects are done. You draw ideas from your permanent notes, but you don’t change them for the projects - keep the modifications for the project-specific context inside the project notes.
Synthesis: contextual hub notes
Notes that act as single entry points into a theme - a question you keep returning to, a problem you keep solving, a domain you keep dipping back into. Write a short prose intro and link out to the relevant permanent notes inline.
The point is to catch yourself when you’ve forgotten what you’ve already written. You can’t search for an idea you don’t remember having. The hub is the thing you stumble onto via the graph or backlinks, and it surfaces the forgotten material for you. This is also the answer to the “use specific contextual tags” advice from Ahrens - in a digital vault, that work lives better in hub notes than in tags, where vocabulary sprawl quickly makes tags un-queryable.
Distinct from connection notes, which join two specific ideas, and project notes, which are bound to a specific project. A hub is broader and more durable - it grows as you keep returning to the theme.