The best informal de?nition of the Semantic Web is maybe found in the May 2001Scienti?cAmericanarticle TheSemanticWeb (Berners-Leeetal. ), which says TheSemanticWebisanextensionofthecurrentWebinwhichinformation is given well-de?ned meaning, better enabling computers and people to work in cooperation. People who work on the Semantic Web quite often base their work on the famous semantic web tower, a product of Tim Berners-Lee s inspiring drawing on whiteboards. The lowest level is the level of character representation (Unicode) and the identi?cation of resources on the Web (URIs). The highest...