Keywords = data, tags = metadata?
I'm not quite sure whether or how I'll actually implement this or whether it will really make sense at all once I've thought it through and tried to apply it, but I'm thinking it might be useful to make a distinction between keywords (understood as part of a note's data/content) and tags (understood as metadata about the note itself as an "object"). Tags might be used, for example, to identify summary or table-of-contents notes, or notes that are the start of a Folgezettel sequence if you use those, or notes about the organizational principles of the Zettelkasten itself. (One thing I'm thinking of here is Pirsig's index card categories in Lila.) Any thoughts or experience?