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.
This article is an introduction to the "brother and sister" Web Service protocols named Search/Retrieve Web Service (SRW) and Search/Retrieve URL Service (SRU) with an emphasis on the later.