The semantic Web is considered an extension of the World Wide Web to the degree that computers interpret data and transmit that data in a way that is very perceptive to a user. In other words, the semantics of information and services on the Web is defined, making it possible for the Web to understand and satisfy the requests of people who use the content.
Semantics refers to the meaning of words. The semantic Web derives from W3C director Tim Berners-Lee's vision of the Web as a universal medium for data, information, and knowledge exchange. This information exchange takes documents with computer-comprehensible meaning (semantics) and puts them on the Web. Tim Berners-Lee has said "People keep asking what Web 3.0 is. I think maybe when you've got an overlay of scalable vector graphics - everything rippling and folding and looking misty - on Web 2.0 and access to a semantic Web integrated across a huge space of data, you'll have access to an unbelievable data resource."