To facilitate the development of the Semantic Web, we propose in this thesis a general automatic ontology-building algorithm which, given a pool of potential terms and a set of relationships to include in the ontology, can utilize information gathered from Google queries to build a full ontology for a certain domain. We utilized this ontology-building algorithm as part of a larger system to tag computer tutorials for three systems with different kinds of metadata, and index the tagged documents into a search engine. Our evaluation of the resultant search engine indicates that our automatic ontology-building algorithm is able to build relatively good-quality ontologies and utilize this ontology to effectively apply metadata to documents.