22. A system comprising: one or more computers; and a computer-readable medium coupled to the one or more computers having instructions stored thereon which, when executed by the one or more computers, cause the one or more computers to perform operations comprising: obtaining a set of search results that a search engine identifies as responsive to a search query; obtaining a respective snippet for each of first multiple search results, wherein the first multiple search results are selected from among the set of search results; providing, for display, a search engine results page that includes (i) the first multiple search results from among the set of search results that the search engine identifies as responsive to the search query, (ii) the respective snippet for each of the first multiple search results, and (iii) a text entry field for entering a refinement to the search query; receiving data indicating the refinement to the search query that is entered through the text entry field on the search engine results page; in response to receiving the data indicating the refinement to the search query, obtaining a subset of the set of search results, wherein each search result of the subset of search results references a respective resource that satisfies the refinement, and wherein the subset of search results are obtained without instructing the search engine to perform a subsequent search; obtaining a respective updated snippet for each of second multiple search results, wherein the second multiple search results are selected from among the subset of search results; and providing, for display, an updated search engine results page that includes (i) the second multiple search results that are selected from among the subset of the search results, and (ii) the respective updated snippet for each of the second multiple search results.
22. A system comprising: one or more computers; and a computer-readable medium coupled to the one or more computers having instructions stored thereon which, when executed by the one or more computers, cause the one or more computers to perform operations comprising: obtaining a set of search results that a search engine identifies as responsive to a search query; obtaining a respective snippet for each of first multiple search results, wherein the first multiple search results are selected from among the set of search results; providing, for display, a search engine results page that includes (i) the first multiple search results from among the set of search results that the search engine identifies as responsive to the search query, (ii) the respective snippet for each of the first multiple search results, and (iii) a text entry field for entering a refinement to the search query; receiving data indicating the refinement to the search query that is entered through the text entry field on the search engine results page; in response to receiving the data indicating the refinement to the search query, obtaining a subset of the set of search results, wherein each search result of the subset of search results references a respective resource that satisfies the refinement, and wherein the subset of search results are obtained without instructing the search engine to perform a subsequent search; obtaining a respective updated snippet for each of second multiple search results, wherein the second multiple search results are selected from among the subset of search results; and providing, for display, an updated search engine results page that includes (i) the second multiple search results that are selected from among the subset of the search results, and (ii) the respective updated snippet for each of the second multiple search results. 25. The system of claim 22 , wherein providing, for display, the updated search engine results page comprises replacing a particular search result presented on the search engine results page with a search result not included in the search results presented on the search engine results page.