1. A computer-implemented method of registering an ontology with a search engine provider, comprising: receiving an ontology definition comprising a plurality of terms from an ontology owner; storing the ontology definition on a search engine server; creating an ontology index based on the ontology definition and a keyword index, wherein: the keyword index includes a plurality of relationships between a plurality of keywords and a plurality of documents residing on a network; the ontology index includes a plurality of relationships between the plurality of terms and the plurality of documents residing on the network; and storing the ontology index.