Search is iterative. Search Engines are not.
Search engines are one shot deals. Each search is an independent event, never leveraging the previous search and never supporting the next search. Search engines are dependent on the highly variable skills and knowledge of each user, who are equally variable in their search success.
1Result learns from previous searches by each and every user to help the next user succeed beyond their own level of skill or knowledge. This helps conserve institutional knowledge, so that a company retains the search skill and knowledge long after an associate leaves the company.