You could build an ontology in RDF [1] or OWL [2] and link the grammars together.
FOAF [3] was a means of describing your friends and social connections, and it allowed rich annotation.
No tools were ever built around this because by the time it started taking off, Facebook and MySpace were already a thing.
The great thing about these technologies is that the graph is public and you could write tools to ingest, export, and exchange the information. We never got to that, though.
The technology was centered around graphs and triple stores, allowing you to apply subject-predicate labels to anything. The URI became a central node, document, and ontology identification scheme.
There were languages like SPARQL for querying rich triplestore databases, but they never really took off. Again, Google and Facebook were already huge by the time these started to mature.
If you think the promise of blockchain is exciting, you should take a look at what the Semantic Web could have been...
[1] https://www.w3.org/TR/rdf-primer/