I noticed that the tags and are now synonyms for .

(I only found the discussion Schema.org vs Microdata where Stephen Ostermiller’s answer mentions that "schema.org" (but not "microformats") got merged with "microdata".)

I don’t think that and should be synonyms for . All three are separate things.

Microdata is a syntax, nothing more. It doesn’t come with any vocabularies.

(Same is true for RDFa, but this is, at least currently, a tag on its own, as it should be.)

Schema.org is a vocabulary, which can used with Microdata and RDFa (and possibly more syntaxes yet to come).

Microformats is a syntax coupled with vocabularies. Their vocabularies can’t be used with Microdata or RDFa, and Schema.org can’t be used as Microformat.


  • When a user has a problem with her use of RDFa and schema.org, she would have to tag her question with , although she doesn’t use any Microdata at all.
  • When a user has problem with his use of Microformats, he would have to tag his question with , although he doesn’t use any Microdata at all.
  • When a user has a question about the correct choice/use of Schema.org properties, she would have to tag her question with , although it doesn’t contain any code (as the question is about the semantics/meaning of the vocabulary, not about a specific implementation in a syntax).

3 Answers 3


I agree that should be separate from . We certainly didn't decide to merge those two here: Schema.org vs Microdata (although the tags were both mentioned as possible candidates for merge.)

It looks like that merge was done October 30th: https://webmasters.stackexchange.com/tags/synonyms but I'm not sure why.

EDIT: I have now deleted two tag synonyms. Now we can have separate tags:

The next step would be to tags some questions and write tag wikis.

  • What is the process here, can we do this? There seems to be consensus (given a +5/-0 for the question and a +3/-0 for this answer).
    – unor
    Commented Jun 5, 2015 at 22:51
  • 1
    @unor I have deleted tag synonyms. Can you tag some questions and write tag wikis? Commented Jun 9, 2015 at 12:18
  • Thanks :) Yes, I’ll do it (later today or tomorrow).
    – unor
    Commented Jun 9, 2015 at 12:34

Hmm lets analyze the first sentence on Schema.org:

This site provides a collection of schemas that webmasters can use to markup HTML pages in ways recognized by major search providers, and that can also be used for structured data interoperability (e.g. in JSON).

It is a schema of structured data that is delivered via specific markup -- it is not the markup [carrier] itself.

So I use Schema.org with JSON-LD. Schema.org lists JSON-LD examples. Google recommends JSON-LD. But JSON-LD is not microdata, nor is JSON-LD Schema.org. Same with microdata. Microdata is not Schema.org, nor is Schema.org microdata. Schema.org is Schema.org, or in a broader sense, simply an agreed upon way of delivering structured/semantic data.

By using the current Schema.org tag I am thrown into microdata even when there is not a shred of microdata in the questions: Example 1, Example 2.

In the end, just seperate Schema.org from microdata. It is a flexible model and a big enough animal to survive on its own in the SE tag forest.


Schema.org only supports microdata, not RDFa or microformat. According to their FAQ:

Q: Why microdata? Why not RDFa or microformats?

Focusing on microdata was a pragmatic decision. Supporting multiple syntaxes makes documentation for webmasters more complex and introduces more overhead in terms of defining new formats. Microformats are concise and easy to understand, but they don't offer an open extensibility mechanism and the reuse of the class tag can cause conflicts with website CSS. RDFa is extensible and very expressive, but the substantial complexity of the language has contributed to slower adoption. Microdata is the most recent well-known standard, created along with HTML5. It strikes a balance between extensibility and simplicity, and is most suitable for building the schema.org. Google and Yahoo! have in the past supported both microformats and RDFa for certain schemas and will continue to support these syntaxes for those schemas. We will also be monitoring the web for RDFa and microformats adoption and if they pick up, we will look into supporting these syntaxes. Also read the section on the data model for more on RDFa.

So your first two examples of using schema.org with RDFa or Microformats shouldn't happen. The questions should be tagged with and respectively, but not with .

Your third example is technically different, but when we had separate tags for "microdata" and "schema.org" they tended to be used interchangeably. It was especially true that questons about microdata would get tagged as schema.org because that is where the person asking the question found out about microdata.

If somebody does want to ask about vocabulary but not about code, they can use . It might also be appropriate to create a tag such as "semantic-vocabulary" for such instances.

  • Regarding schema.org and RDFa, see the section "Mapping to RDFa Lite" in Data Model: "all of Schema.org can be used with the RDFa Lite syntax as is"
    – unor
    Commented Dec 12, 2013 at 16:19
  • Compatible, but modifications are required. None of the code available on the schema.org site is in RDFa Lite. Commented Dec 12, 2013 at 16:22
  • The examples are only those, (informative) examples. It’s about the (normative) URIs and their definitions. They decided to focus on Microdata for the examples. That doesn’t mean that only the examples are valid. For example the documentation for the additionalType property even refers to RDFa.
    – unor
    Commented Dec 12, 2013 at 16:23
  • The site schema.org now also includes code examples in RDFa and JSON-LD for many types, e.g. for Person.
    – unor
    Commented Apr 4, 2014 at 14:31

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