a very nice write up of talis at readwriteweb - http://www.readwriteweb.com/archives/talis_semantic_web.php "Basically, data in the Platform is stored in aptly-named structures called 'stores', which allow data to be accessed using metadata (machine readable descriptors utilizing RDF). This data can then be accessed and linked from the Web, allowing easy access to self-managed data stores, while still enabling the RDF Semantic components to sort and examine the data. Linked in with the semantic filtering and data- management is a strong control of data and their interrelations. Any element of the data can be matched and controlled, allowing access to relevant data rather than just returning simple search results. An example Talis gives for this is in a retail context: a product can be found in multiple stores; but using relevant retrieval, data can be returned for a specific store. "The upshot of the platform in combination with the Talis Community License is that semantic mashups can be created. One such, a Firefox plugin ... allows you to see which libraries across the UK hold a copy of the book you happen to be looking for on Amazon."