Do we have a RDF net?

Question

We can give some information in HTML form. Then different peoples provides different HTML pages which are interconnected and in this way we get WWW. Information can also be given in the with the usage of RDF form (let say XML implementation of RDF). Different peoples can provide different RDF documents and... I expect that we can get a kind of RDF-based Internet. But the problem is that I do not see how RDF can link to each other. Is it possible? Do we have a net of RDF files (RDF files which point to each other and which can be browsed like WWW)?

Answer 1

RDF was designed from the ground up to be used as a metadata annotation format to describe other content, not as a way to store or transfer the content itself. The "RDF Internet" you mention (also commonly called the Semantic Web) is a series of assertions and annotations layered on top of the normal, loosely-structured content already available on the 'net.

Remember, the abbreviation RDF stands for Resource Description Framework. Its entire purpose is to describe resources, not encode their payload.

That being said, you can use RDF to talk about other RDF tuples using reification, which is simply a way of reasoning about logical assertions. In the RDF model, reification turns a single RDF tuple into a resource that can itself then be described with other RDF tuples. As an example, if we had the following RDF statment:

• {foaf:name, http://rcoder.net/about#me, "Lennon Day-Reynolds"}

...we could assign it a unique URI:

• http://rcoder.net/about?format=foaf#name

...after which time it can be freely annotated with other RDF tuples:

• {dc:date, http://rcoder.net/about?format=foaf#name, 2009-09-30T10:24:180-07:00}

You might want to also peruse the W3C and Wikipedia articles on reification for more info.

Answer 2

Not yet - many datasets are islands, but there is a community trying to make it happen. Sites such as linkeddata.org would be a good place to look for more info. That most of the linked site fit on a single page diagram gives you a clue as to how big the RDF net is at the moment compared with the www.