'The Semantic Web is an extension of the current web in which information is given welldefined meaning, better enabling computers and people to work in cooperation' (Berners-Lee et al. 2001) . The Semantic Web and computable information are the visions of Tim Berners-Lee, the creator of the World Wide Web (familiar to us through Google 71 and other search engines), who views this future Web as a web of data, 'like a global database', where 'information is given well-defined meaning, better enabling computers and people to work in cooperation'. Making information on the Web 'semantic' (or meaningful) means much more efficient searching 'as though it were one giant database, rather than one giant book' (Berners-Lee 1998).