"Text search engines are of course good for searching the text in documents, but the Semantic Web isn't text documents, it is data. It isn't obvious what the killer apps will be - there are many contenders. We know that the sort of query you do on data is different: the SPARQL standard defines a query protocol which allows application builders to query remote data stores. So that is one sort of query on data which is different from text search."

"One thing to always remember is that the Web of the future will have BOTH documents and data. The Semantic Web will not supersede the current Web. They will coexist. The techniques for searching and surfing the different aspects will be different but will connect. Text search engines don't have to go out of fashion."

Tim Berners-Lee - timbl's blog - Semantic Web in the News

"Do you have a URI for yourself? If you are reading this blog and you have the ability to publish stuff on the web, then you can make a FOAF page, and you can give yourself a URI. A lot of people have published data about themselves without using a URI for themselves. This means I can't refer to them in other data. So please take a minute to give yourself a URI. If you have a FOAF page, you may just have to add rdf:about="" and voila you have a URI http://example.com/Alan/foaf.rdf#ABC. (I suggest you use your initials for the last bit). Check it works in the Tabulator. The URI will start with 'http' (so I can look it up using HTTP) and it will have # in it, so the URI of your foaf file is different from the URI for you. Me, I make my foaf file in N3 and convert it to the foaf file in RDF. that's my choice. The AWWW says that everything of importance deserves a URI. Go ahead and give yourself a URI. You deserve it!"

Tim Berners-Lee - timbl's blog - Give Yourself a URI

The semantic web comprises the standards and tools of XML, XML Schema, RDF, RDF Schema and OWL that are organized in the Semantic Web Stack. The OWL Web Ontology Language Overview describes the function and relationship of each of these components of the semantic web:

• XML provides an elemental syntax for content structure within documents, yet associates no semantics with the meaning of the content contained within.
• XML Schema is a language for providing and restricting the structure and content of elements contained within XML documents.
• RDF is a simple language for expressing data models, which refer to objects ("resources") and their relationships. An RDF-based model can be represented in XML syntax.
• RDF Schema is a vocabulary for describing properties and classes of RDF-based resources, with semantics for generalized-hierarchies of such properties and classes.
• OWL adds more vocabulary for describing properties and classes: among others, relations between classes (e.g. disjointness), cardinality (e.g. "exactly one"), equality, richer typing of properties, characteristics of properties (e.g. symmetry), and enumerated classes.
• SPARQL is a protocol and query language for semantic web data sources.

Source: http://en.wikipedia.org/wiki/Semantic_Web

Further Resources:
http://dig.csail.mit.edu/breadcrumbs/blog/4
http://www.w3.org/TR/owl-features/
http://simile.mit.edu/
http://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenD...
http://www.w3.org/2001/sw/sweo/