One of my collegaues called the other day and asked if we still relied on the distinction between intensional and extensional sets (really intensionally and extensionally defined sets). Yes, even more so now.
This lecture elaborates on RDF, RDFS, and SOAP starting from a short recap of XML, and the history of the W3C and the development of "open standard recommendations". We also compare RDF triples with DOGMA lexons. We finalise by listing shortcomings of RDFS regarding semantics, and give short overview of the history of OWL as one answer to this. A full elaboration on OWL and description logic is for another lecture.