A search engine that is client-side, provides high performance and creates a user preference history record relative to a knowledge base is provided. The more time the user spends using the search engine, the more the history record is updated, refined, and translated into personal preferences relative to that knowledge base. The invention is natural language based. In addition, it is applicable to a variety of knowledge bases, each which may have their own associated history record, and can be adapted to other applications such as on-line help, interactive training, wizard functions, virtual chat sessions, intelligent bots, etc.