Chris Bizer, Richard Cyganiak, and Tom Heath have just published a Linked Data Publishing Tutorial that provides a guide to the mechanics of Linked Data injection into the Semantic Data Web.

On different, but related, thread, Mike Bergman recently penned a post titled: What is the Structured Web?. Both of these public contributions shed light on the "Information BUS" essence of the World Wide Web by describing the evolving nature of the payload shuttled by the BUS.

What is an Information BUS?

Middleware infrastructure for shuttling "Information" between endpoints using a messaging protocol.

The Web is the dominant Information BUS within the Network Computer we know as the "Internet". It uses HTTP to shuttle information payloads between "Data Sources" and "Information Consumers" - what happens when we interact with Web via User Agents / Clients (e.g Browsers).

What are Web Information Payloads?

HTTP transported streams of contextualized data. Hence the terms: "Information Resource" and "Non Information" when reading material related to http-range-14 and Web Architecture. For example, an (X)HTML document is a specific data context (representation) that enables us to perceive, or comprehend, a data stream originating from a Web Server as a Web Page. On the other hand, if the payload lacks contextualized data, a fundamental Web requirement, then the resource is referred to as a "Non Information" resource. Of course, there is really no such thing as a "Non Information" resource, but with regards to Web Architecture, it's the short way of saying: "the Web Transmits Information only". That said, I prefer to refer to these "Non Information" resources as "Data Sources", are term well understood in the world of Data Access Middleware (ODBC, JDBC, OLEDB, ADO.NET etc.) and Database Management Systems (Relational, Objec-Relational, Object etc).

Examples of Information Resource and Data Source URIs:

Explanation: The Information Resource is a conduit to the Entity identified by Data Source (an entity in my RDF Data Space that is the Subject or Object of one of more Triple based Statements. The triples in question can that can be represented as an RDF resource when transmitted over the Web via an Information Resource that takes the form of a SPARQL REST Service URL or a Physical RDF based Information Resource URL).

What about Structured Data?

Prior to the emergence of the Semantic Data Web, the payloads shuttled across the Web Information BUS comprised primarily of the following:

  1. HTML - Web Resource with presentation focused structure (Web 1.0 dominant payload form)
  2. XML - Web Resource with structure that separates presentation and data (Web 2.0's dominant payload form).

The Semantic Data Web simply adds RDF to the payload formats that shuttle the Web Information BUS. RDF addresses formal data structure which XML doesn't cover since it is semi-structured (distinct data entities aren't formally discernible). In a nutshell, an RDF payload is basically a conceptual model database packaged as an Information Resource. It's comprised of granular data items called "Entities", that expose fine grained properties values, individual and/or group characteristics (attributes), and relationships (associations) with other Entities.

Where is this all headed?

The Web is in the final stages of the 3rd phase of it's evolution. A phase characterized by the shuttling of structured data payloads (RDF) alongside less data oriented payloads (HTML, XHTML, XML etc.). As you can see, Linked Data and Structured Data are both terms used to describe the addition of more data centric payloads to the Web. Thus, you could view the process of creating a Structured Web of Linked Data as follows:

  1. Identify or Create Structured Data Sources
  2. Name these Data Sources using Data Source URIs
  3. Expose Structured Data Sources to the Web as Linked Data using Information Resource (conduit) URIs

Conclusions

The Semantic Data Web is an evolution of the current Web (an Information Space) that adds structured data payloads (RDF) to current, less data oriented, structured payloads (HTML, XHTML, XML, and others).

The Semantic Data Web is increasingly seen as an inevitability because it's rapidly reaching the point of critical mass (i.e. network effect kick-in). As a result, Data Web emphasis is moving away from: "What is the Semantic Data Web?" To: "How will Semantic Data Web make our globally interconnected village an even better place?", relative to the contributions accrued from the Web thus far. Remember, the initial "Document Web" (Web 1.0) bootstrapped because of the benefits it delivered to blurb-style content publishing (remember the term electronic brochure-ware?). Likewise, in the case of the "Services Web" (Web 2.0), the bootstrap occurred because it delivered platform independence to Web Application Developers - enabling them to expose application logic behind Web Services. It is my expectation that the Data Integration prowess of the Data Web will create a value exchange realm for data architects and other practitioners from the database and data access realms.

Related Items

  1. Mike Bergman's post about Semi-Structured Data
  2. My Posts covering Structured and Un-Structured Containers