A document versus a tree
Markdown begins with a file. You type plain text, use simple formatting syntax and can open the result in many editors. An outliner begins with an item in a hierarchy. You add children, indent, collapse and move sections as your thinking changes.
Markdown is excellent when the document is the thing you want to preserve: a README, article, specification or plain-text archive. Outlining is excellent when the relationship between ideas is still changing: a project plan, book structure, research tree or set of meeting decisions.
What Markdown does well
What outliners do well
Choose based on what changes most
If you primarily revise prose inside files, Markdown is a strong default. If you constantly rearrange sections, turn ideas into tasks or need one connected workspace for notes and projects, an outliner is usually more natural. Many people write the final document in Markdown while using an outliner to plan and organise everything behind it.
Where TreeNote fits
TreeNote is an outliner rather than a folder of Markdown files. It is designed for work where hierarchy, movement and retrieval matter every day. OPML import and export keep the outline portable when you need to move it — there is no Markdown file import or export, so a vault of Markdown notes converts to OPML first. If you are weighing it against a Markdown-based tool, the Obsidian comparison is the closest case.
Questions
Plan in a tree. Publish in a file.
Most people need both — the question is which one holds the thinking.
Put these ideas into practice
TreeNote provides a fast, flexible outliner built around these principles. No sign up required to start.