Semantic Web

• Semantic Web

The Semantic Web is about two things. It is about common formats for integration and combination of data drawn from diverse sources, where on the original Web mainly concentrated on the interchange of documents. It is also about language for recording how the data relates to real world objects. That allows a person, or a machine, to start off in one database, and then move through an unending set of databases which are connected not by wires but by being about the same thing.
http://www.w3.org/2001/sw/

The Semantic Web is the extension of the World Wide Web that enables people to share content beyond the boundaries of applications and websites.
http://semanticweb.org/wiki/Main_Page

• OWL Web Ontology

The OWL Web Ontology Language is designed for use by applications that need to process the content of information instead of just presenting information to humans. OWL facilitates greater machine interpretability of Web content than that supported by XML, RDF, and RDF Schema (RDF-S) by providing additional vocabulary along with a formal semantics. OWL has three increasingly-expressive sublanguages: OWL Lite, OWL DL, and OWL Full.
http://www.w3.org/TR/owl-features/

The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. The languages are characterised by formal semantics and RDF/XML-based serializations for the Semantic Web
http://en.wikipedia.org/wiki/Web_Ontology_Language

• What is the Semantic Web?

The Semantic Web is a web that is able to describe things in a way that computers can understand.
    The Beatles was a popular band from Liverpool.
    John Lennon was a member of the Beatles.
    "Hey Jude" was recorded by the Beatles.

Sentences like the ones above can be understood by people. But how can they be understood by computers?
Statements are built with syntax rules. The syntax of a language defines the rules for building the language statements. But how can syntax become semantic?
This is what the Semantic Web is all about. Describing things in a way that computers applications can understand it.
The Semantic Web is not about links between web pages.
The Semantic Web describes the relationships between things (like A is a part of B and Y is a member of  Z) and the properties of things (like size, weight, age, and price)


The Resource Description Framework

The RDF (Resource Description Framework) is a language for describing information and resources on the web.
Putting information into RDF files, makes it possible for computer programs ("web spiders") to search, discover, pick up, collect, analyze and process information from the web.
The Semantic Web uses RDF to describe web resources.


RDF was developed by people with academic background in logic and artificial intelligence. For traditional developers it is not very easy to understand.
http://www.w3schools.com/web/web_semantic.asp