9. A system for generating advertisements for display to a user, the system comprising: a computer system including; a query engine configured to receive a query over a network connection from the user, the query including a plurality of keywords, the query engine being configured to identify a domain based on the query; and an advertisement selection engine in communication with the query engine, the advertisement selection engine selecting a domain based on the query and a hierarchy of predicates for the domain; wherein the advertisement engine is configured to determine if at least one term in the query matches at least one predicate value of an entry, the advertisement engine being configured to determine a corresponding position in the hierarchy for the at least one predicate value matching the at least one term in the query, wherein the advertisement engine generates inverted lists for each keyword of the plurality of keywords based on the hierarchy and generates a plurality of queries wherein a query of the plurality of queries is generated for each entry in the inverted list, wherein a web page is updated based on at least one query of the plurality of queries.
9. A system for generating advertisements for display to a user, the system comprising: a computer system including; a query engine configured to receive a query over a network connection from the user, the query including a plurality of keywords, the query engine being configured to identify a domain based on the query; and an advertisement selection engine in communication with the query engine, the advertisement selection engine selecting a domain based on the query and a hierarchy of predicates for the domain; wherein the advertisement engine is configured to determine if at least one term in the query matches at least one predicate value of an entry, the advertisement engine being configured to determine a corresponding position in the hierarchy for the at least one predicate value matching the at least one term in the query, wherein the advertisement engine generates inverted lists for each keyword of the plurality of keywords based on the hierarchy and generates a plurality of queries wherein a query of the plurality of queries is generated for each entry in the inverted list, wherein a web page is updated based on at least one query of the plurality of queries. 12. The system according to claim 9 , wherein the advertisement engine includes a query combination block configured to combine the plurality of queries.