'Designing better file organization around tags, not hierarchies' by Nayuki [1] (HN thread [2]) is an essay about such filename-less, tagging-based systems, covering prior art, technical background, and user experience. It's a thorough look at what has already been done, what works, what's clunky, and brainstorms about where we can still go.

[1] https://www.nayuki.io/page/designing-better-file-organizatio... [2] https://news.ycombinator.com/item?id=16763235