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Re: Official response to RDF-ISSUE-132: JSON-LD/RDF Alignment

From: Dan Brickley <danbri@danbri.org>
Date: Wed, 12 Jun 2013 09:54:32 +0100
Message-ID: <CAFfrAFpo_biXh7cqBD8Cd5GRL=-RL+h2xbe0-ugOhB1E6GjL0A@mail.gmail.com>
To: Markus Lanthaler <markus.lanthaler@gmx.net>, Pat Hayes <phayes@ihmc.us>, Sandro Hawke <sandro@w3.org>
Cc: public-rdf-comments <public-rdf-comments@w3.org>
I have been reading some of the threads about whether JSON-LD should
cite RDF in its opening paragraphs. I believe it should.

Looking at http://www.w3.org/TR/2013/WD-json-ld-20130411/#introduction

"1. Introduction

This section is non-normative.

Linked Data is a technique for creating a network of inter-connected
data across different documents and Web sites. In general, Linked Data
has four properties: 1) it uses IRIs to name things; 2) it uses HTTP
IRIs for those names; 3) the name IRIs, when dereferenced, provide
more information about the thing; and 4) the data expresses links to
data on other Web sites. These properties allow data published on the
Web to work much like Web pages do today. One can start at one piece
of Linked Data, and follow the links to other pieces of data that are
hosted on different sites across the Web.

JSON-LD is a lightweight syntax to serialize Linked Data in JSON
[RFC4627]. Its design allows existing JSON to be transformed to Linked
Data with minimal changes. JSON-LD is primarily intended to be a way
to use Linked Data in Web-based programming environments, to build
interoperable Web services, and to store Linked Data in JSON-based
storage engines. Since JSON-LD is 100% compatible with JSON, the large
number of JSON parsers and libraries available today can be reused. "

... in that 2nd paragraph you are clearly using the two words "Linked
Data" as a euphemism to avoid saying "W3C RDF". Linked Data isn't
something that can be "serialized" because it has no sufficiently
detailed technical specification. The only way that it makes sense
talking about serializing "Linked Data" is by realizing that the
phrase serves as an informal marketing slogan for RDF. In a formal W3C
recommendation it is entirely appropriate to mention such
dependencies, even if other less formal materials choose not to
emphasize such details.

At schema.org we don't hide that it is based on RDF; we just choose to
document this on the 'datamodel' page, rather than the 'getting
started' page (see http://schema.org/docs/datamodel.html ).

Since people are citing http://www.w3.org/DesignIssues/LinkedData and
talking about its earlier draft that didn't say (RDF, SPARQL,...) one
note:

TimBL writes there (from the earliest drafts) regarding FOAF, "This
linking system was very successful, forming a  growing social network,
and dominating, in 2006, the linked data available on the web.". While
taking issue with the bNode-heavy idioms and /-based term URIs we used
at the time, he does note that FOAF in 2006 was the dominant flavor of
Linked Data out there. In 2006 many blogs, social networks etc. were
experimenting with publishing linked FOAF descriptions. It is worth
noting that this adoption occurred despite FOAF's shameless admission
of being RDF-based. The FOAF specification admitted being based on
RDF, even the file format was RDF/XML, but we still got a lot of data
published despite lack of any concrete incentive for doing so. Mainly
I think because the idea was engaging and the technique was easy to
adopt without reading 100s of specifications. JSON-LD can be engaging
and easy to adopt, even while mentioning it is based on RDF.

I suggest that should be a guideline here. It is entirely right and
proper for JSON-LD to mention its place in the RDF world (rather than
to appear to be somewhat ashamed of it). It is entirely another for
any implementor of JSON-LD to have to go chasing off reading about RDF
(and RDFS and OWL and everything else) before they can get a job done.
So I applaud the idea of making the JSON-LD specification stand alone
in that sense; it just feels you've gone a little too far when it
talks of serializing "Linked Data" rather than RDF graphs. Now if W3C
doesn't have something non-intimidating for "RDF" to hyperlink to in
other specifications, that is quite another problem.

Dan
Received on Wednesday, 12 June 2013 08:54:59 UTC

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