17. The system of claim 15 , wherein the extracted document pattern comprises a specific word that is shared by both the first documents that were retrieved by submitting the lexicon terms to the search engine and the second documents that the query log does not indicate were retrieved by submitting the lexicon terms to the search engine.
17. The system of claim 15 , wherein the extracted document pattern comprises a specific word that is shared by both the first documents that were retrieved by submitting the lexicon terms to the search engine and the second documents that the query log does not indicate were retrieved by submitting the lexicon terms to the search engine. 19. The system of claim 17 , wherein the particular query domain relates to locations, the lexicon term identifies a first location, and the new lexicon term that is added to the lexicon identifies a second location.