The semantic Web: what, why, how, and when

The semantic Web aims to enrich the existing Web with a layer of machine-interpretable metadata so that a computer program can draw conclusions (that is, derive new information) predictably (that is, all programs that receive this information draw the same conclusions from it). The semantic Web has two motivators. The first is data integration, which is a significant bottleneck in many IT applications. The second motivator is more intelligent support for end users. If computer programs can infer consequences of information on the Web, they can give better support in finding information, selecting information sources, personalizing information, combining information from different sources and so on. To achieve these goals, we must meet the challenges of providing i) a syntax for representing metadata ii) vocabularies for expressing the metadata iii) metadata for lots of Web pages