In HTML, structured data is typically added with the syntaxes JSON-LD, Microdata or RDFa. The review of the syntax use is clearly on-topic, just like the use of plain HTML is.
But what about the review of the use of vocabularies/ontologies? The most popular one would be Schema.org. Others are Dublin Core, Open Graph Protocol, FOAF, and many more.
A simple example to clarify
<div typeof="schema:person"> <p property="schema:name">Alice</p> <meta property="schema:parent" content="Bob" /> </div>
Now, a review of the use of Schema.org could suggest that the type must start with an uppercase P, that the property
givenName could be added in addition to the
name property, that the
Person item would ideally get a URI that uniquely identifies this person, and that the
parent property expects a
Person item instead of a string value:
<div typeof="schema:Person" resource="#i"> <p property="schema:name schema:givenName">Alice</p> <div property="schema:parent" typeof="schema:Person"> <meta property="schema:name" content="Bob" /> </div> </div>
We have a few questions that are (partly) about the use of Schema.org:
- Schema.org structure for a news aggregator individual post
- Schema.org combining different categories
- Schema.org microdata code check
- Schema.org Microdata broadest tag check
- Properly mark up multiple person using schema.org microdata
- Semantic HTML5 structure and Google penalty
- Optimizing with microdata and address tag
Questions about this topic on other Stack Exchange sites
If users don’t know how to express something with Schema.org, or if they get warnings/errors in validating tools (like Google’s Structured Data Testing Tool), they can ask on Stack Overflow (tag: schema.org). The same is the case for other vocabularies/ontologies (e.g., foaf, dublin-core, open-graph-protocol etc.).
If users have problems with getting a search result feature based on Schema.org (like Google’s rich results), they can ask on Webmasters SE (tag: schema.org). The same is the case for other vocabularies/ontologies and other features (e.g., open-graph-protocol for features in Facebook).
If users don’t know which vocabulary/ontology to use, they can ask on Open Data SE (tag: ontology).
Except for possibly Code Review SE, there is no SE site where it’s on-topic for users to post their whole structured data and ask if best practices are followed and if their use of the vocabulary/ontology conveys what they want to convey.