Semantic web technologies have had quite a bit of adoption, but it's all pretty niche. JSON-LD embedded in html is the current widely deployed iteration and wer

Semantic web technologies have had quite a bit of adoption, but it's all pretty niche. JSON-LD embedded in html is the current widely deployed iteration and were it not for googles love of structured data it would not be nearly as big. RDF shows up in graph databases a lot too.