Traditional note taking methods, including outliners (Workflowy, Dynalist) necessitate creation of preconceived hierarchies, built “top-down”. In contrast, the heterarchy of Zettelkasten is built organically from “bottom-up” via gradual forming of links between the notes.

Ahrens writes:

[…] don’t start with preconceived categories and fill them with notes. Instead, let order emerge bottom-up by making connections between your notes […]

Per David Clear:

Don’t worry about structure: Don’t worry about putting notes in neat folders or into unique preconceived categories. As Schmidt put it, in a Zettelkasten “there are no privileged positions” and “there is no top and no bottom.” The organization develops organically.

Richard Meadows at lesswrong writes:

the benefits of Zettelkasten accrue in a non-linear fashion over time, as the graph becomes more connected. So even if you ‘get it’ as soon as you start playing around with the cards, you could reasonably expect to reap much greater gains over a timespan of months or years (at least, that’s my experience!).

See also