Swoogle started as a research project at the University of Maryland and never really evolved into a commercial venture. It is still available on the servers of UMBC and its SERP can be seen by pointing the browser to http://swoogle.umbc.edu/.
Swoogle is a search engine whose main goal is to index Semantic Web ontologies, documents, terms and data published on the Web of Data. Swoogle uses a system of crawlers to discover RDF documents and HTML files that have some embedded RDF content.