The Tabulator Extension is an extension for Firefox that provides a human-readable interface for linked data. It is based on the on-line Tabulator, a web-based interface for browsing RDF. Using Tabulator's outline mode, query views, and back-end code, the Tabulator Extension integrates the browsing of linked data directly into the Firefox browser, making for a more natural and seamless experience when browsing linked data on the Web.
DBpedia is a community effort to extract structured information from Wikipedia and to make this information available on the Web. DBpedia allows you to make sophisticated queries against Wikipedia, and to link other data sets on the Web to Wikipedia data.