The Semantic Web is a vision: the idea of having data on the web defined and linked in a way, that it can be used by machines - not just for display purposes, but for using it in various applications.
Examples are: E-commerce requires much richer data. Retailers require this data to flow from wholesalers and wholesalers requires data to flow from producers. Data-exchange of this kind is currently very limited, consisting of tab-delimited dumps or product-specific tables. Specific XML formats for each exchange task improves the situation, but ones misses the network effect of being able to share 90% of the processing software, because the XML data model is too low-level.
But this is only the most basic application: the Semantic Web will change the way we work. E.g. creating software will be just a matter of finding the right components on the Web and a specification document linking to these components. The new software is again just a resource available on the Web.

Indeed, we have the technology available for realizing the Semantic Web, we know how to built terminologies and how to use metadata.
The whole vision depends on agreeing on common standards - something that is used and extended everywhere. Currently worldwide which will help to create the Semantic Web.
Work is going on to realize tools and techniques, which will help to create the Semantic Web.
This site is dedicated to collect these approaches, to explain them and to be a forum for people intere