In the 2007 Xmas issue of the BMJ there is an important article about Web 3.0 -- a new concept: the Semantic Web.
"So what is web 3.0, and why is it called the semantic web? Although both terms are used interchangeably, they convey slightly different, if complementary, views of the new web. The web 3.0 label is often used as a marketing ploy for "the next big thing." An important feature of web 3.0 is that it enables computers to talk to each other so that they can perform the tasks necessary for us to do our work. However, a primary feature of web 3.0 is that it uses metadata—data about data. This will transform the web into a giant database, and organise it along the lines of PubMed, or one of our trusted medical library catalogues."
Here is a .pdf of the article which is also available free at the BMJ: Download web_3.0 Giustini .pdf
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