4. A method as recited in claim 1 , wherein the additional results include a new set of suggested topics, and causes at least some of topics of the new set of suggested topics to be displayed to the first searcher, such that that a hierarchy of topics is formed on the fly for a particular search for the first searcher.
4. A method as recited in claim 1 , wherein the additional results include a new set of suggested topics, and causes at least some of topics of the new set of suggested topics to be displayed to the first searcher, such that that a hierarchy of topics is formed on the fly for a particular search for the first searcher. 5. A method as recited in claim 4 , further comprising: accepting from the searcher new search request information; determining new search results including an identified set of information items and a new set of one or more suggested topics, the new search results determined by applying the one or more search criteria with the accepted new search request information; and presenting to the searcher the new search results.