Definitely, a work in progress!!!!

The concept of web 2.0 is still a vague concept for many users.  Still, the web continues to move on and we're now grappling with the concept of web 3.0 or the semantic web!

Allan Cho and Dean Giustini have written Web 3.0 and health librarians: an introduction which was an interesting starting point.  I say interesting as I didn't fully understand it.

In the article they explain the various stages of the web:

• Web 1.0 (as it was never really called) was the start of the web, where people put up static pages. 
• Web 2.0 was the creation of the social web, this is where users could easily interact with the web, either creating content (blogs, wikis etc) or interacting with people via social networks (e.g. facebook, my-space etc.)
• Web 3.0 is, pretty much, another name for the semantic web.

Web 3.0 is fairly controversial and I may not have grasped the subtleties, but here goes.

In a nutshell it appears that the semantic web is applying descriptive data (AKA meta-data) to pages on the web.  So you may have a document that has a load of text on it.  A computer can 'read' the text but does not 'understand' it.  In the semantic web the document would be 'marked up' with loads of descriptive data to facilitate the computer 'understanding' what it's about.  This would require standardised special descriptive languages to ensure consistency.

Within Web 3.0 there appears to be two separate approaches, top down and bottom up.

Bottom Up

This is where publishers of material add the extra descriptive data themselves.

Top Down

This is where computers (possibly aggregators such as Google) analyse the text and assign their own descriptive meta-data.

It should be noted that meta-data is extensively used at the moment.  My view is that web 3.0 is mainly about expanding the amount of standardised meta-data and allowing better manipulation of this.

I picture web 3.0 as taking a document and highlighting bits of it in marker pen.  The marker pen is not seen by the user but is seen and 'understood' by the computer.

I'm still not convinced that the semantic web will take off.  Perhaps if I could see and use and aspect of the semantic web I'd be better able to appreciate it.  While we have enthusiasts like Dean there are other people I respect who think it's ain't going to happen/work. 

Some additional reading:

• The Semantic Web: The Origins of Artificial Intelligence Redux
• The Semantic Web (wikipedia)
• Semantic web patterns