Semantic Web Search Engine (SWSE)
http://www.swse.org/

Because of the inherent semantics of RDF and other SW languages, the search and information retrieval capabilities of SWSE are potentially much more powerful than those of current search engines. The use of vocabularies and ontologies makes it possible to apply powerful inferencing techniques and get much more accurate search results. Beta. Indexing a crawl of 1 billion facts (May 2010) + 1 billion inferred facts. Running on one machine without result size cut-off. May be a bit slow for larger queries. Looks best in FireFox. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog. This will be added to the Semantic Web Research section of Deep Web Research.