Re: Role of RDFa in 2016

> On Oct 3, 2016, at 7:31 PM, Kevin Ford <kefo@3windmills.com> wrote:
> 
> Dear All,
> 
> Although I feel like I will be flamed for this question, I was interested in hearing some opinions about the role of RDFa vs JSON-LD (embedded in the HTML header, let's say) in HTML now that the latter has become more accepted, at least when it comes to one major search engine.  Has that weakened the use case for, or role of, RDFa?
> 
> To ask a broad question: Who/What consumers make regular use of RDFa (because there is no alternate/easy serialization to obtain)?

Most places that are interested in structured data on the web now consume RDFa, Microdata and JSON-LD, from what I see.

> To ask a slightly more targeted question, if you publish a data service that responds to content-negotiation (and which can embed JSON-LD in the header and which can also provide rel="alternate" links in the header), is it reasonable to conclude that RDFa is overkill in such a scenario?

Probably. If you can provide a more pure data view, either embedded, via content negotiation, or rel=“alternate” (or similar) you’re probably better to do that. Of these, the “alternate” link relation is less likely to work well IMHO. Consumers of RDF commonly use content negotiation, so I would favor this, or embed it in a script tag. Note that you can also embed Turtle in a script tag using @type=“text/turtle” on the element.

> I recognize the use case for RDFa is much deeper than search engines, but I also suspect that in most cases when a service publishes RDFa in the HTML, that same service likely has made a 'cleaner' alternate serialization available.

This really depends on how an HTML page is constructed. If it is built from an underlying database, then you can probably just as well provide the alternative “pure” data formats. However, if it is composed of different elements, possibly from an editing tool, or copy/paste, then a form such as RDFa or Microdata is more natural. This would also help keep the content of the HTML page in sync with a different format. Note that copy/paste was a specific goal of Microdata, although this was abandoned by WHATWG. Still, the attribute nature of both RDFa and Microdata is much more compatible with a composition scenario. Of those two, RDFa certainly provides greater fidelity in marking up your data, at the cost of more complexity, but at this point, we should be beyond hand-authoring considerations.

Gregg

> --Kevin
>

Received on Tuesday, 4 October 2016 18:30:14 UTC