In an earlier note, I claimed that (01)
> Twitter, Facebook, and LinkedIn have
> huge graph databases, but none of them use RDF. (02)
And I received an offline reply: (03)
> I was under the impression that Facebook's OpenGraph is based on RDFa
> [OGP wrote] To turn your web pages into graph objects, you need to
> add basic metadata to your page. We've based the initial version of
> the protocol on RDFa <http://en.wikipedia.org/wiki/RDFa>... (04)
As I have said many times, the only relationship between RDF and RDFa
is in the three letters R D F. If you follow that pointer to ogp.me,
you'll find the following example in HTML. (05)
> <html prefix="og: http://ogp.me/ns#">
> <title>The Rock (1996)</title>
> <meta property="og:title" content="The Rock" />
> <meta property="og:type" content="video.movie" />
> <meta property="og:url" content="http://www.imdb.com/title/tt0117500/" />
> <meta property="og:image" content="http://ia.media-imdb.com/images/rock.jpg"
> </html> (06)
Just above that example is the following explanation: (07)
> The four required properties for every page are:
> og:title - The title of your object as it should appear within the graph.
> og:type - The type of your object, e.g., "video.movie".
> og:image - An image URL which should represent your object within the graph.
> og:url - The canonical URL of your object that will be used as its permanent
or any other language to generate JSON, CLIF, CGIF, or SQL.
If you follow the links in the following URLs, you'll find that
the native language for the Facebook API is JSON. (09)
> Indeed, these two posts
> seem to indicate that they are using some version of RDFs and RDFa. (010)
Note that those are W3C web sites, which follow the party line. (011)
When a project X is failing, management will resort to CYA measures.
A typical response is to rename something successful with the name X
so that they can tell the board of directors and the investors that
the money poured into X was not wasted. (012)
In this case, they took a minor extension to HTML and called it RDFa.
Then they used RDFS to specify a mapping to RDF. But nobody actually
uses that mapping to RDF. What they use is JSON, which is a subset
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