Linked data is a hot topic today. However, it is much more than just using hyperlinks in a web document. It is rather data linked throughout the web. Instead of just clicking on a hyperlink to one other link, you click on a link to links. This is possible thanks to relating data together instead of just documents.
See more by watching Tim Berners-Lee on linked data at TED filed Feb. 2009: the next open Web of linked data.