[gambler]

Indeed. It could be useful for rendering custom tags, but the problem with semantic content is that there needs to be an entry point somewhere.

No matter how I think about it, it seems that at some level there always needs to be a way to say "this piece of data is officially ba073188-8bd6-47a7-9065-eb55c4a8b908 (year of publishing)". Which means that whenever you see another ba073188-8bd6-47a7-9065-eb55c4a8b908, you and all your tools know the data refers to the same kind of thing.

Everything else can be bootstrapped.

XML solved this through namespaces + URLs. IMO, it was a cludgy and inelegant solution with weird syntax and unnecessary levels of abstraction, but at least it was something.