Anyone who looks into my experimental outliner with notes, clown, is sure to notice that the native data format is EDN (Extensible Data Notation). The canonical data representation for outlines is OPML (Outline Processor Markup Language) and it is well suited for that purpose. It’s a dialect of XML especially adapted to outliners. So, why use EDN? Rich Hickey gives a good rationale at the link above. But for me it boils down to a few things.
Questions about note-taking are very popular on Hacker News. I am always interested in the responses. It seems like developers are always interested in the best tools and methodologies. Me too. I’ve been researching and using different approaches for decades. Over all that time, I’ve written thousands of notes, both short and long. Most notes become uninteresting after awhile and are just erased. But thousands have persisted for many years because I still refer to them.