9. A system comprising: one or more processors and one or more storage devices storing instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising: identifying a webpage that is relevant to a search query; identifying a first snippet for the webpage and a second snippet for the webpage, the first snippet being generated using titles for a plurality of subpages corresponding to the webpage, the webpage and the plurality of sub-pages being associated with a same web site, the second snippet being generated based on text from the webpage; determining a measure of relevance of the first snippet to the webpage; determining a measure of relevance of the second snippet to the webpage, wherein the measure of relevance of the second snippet to the webpage is based on one or more meta-descriptions associated with the webpage; and providing a search result document that includes one of the first snippet or the second snippet, the first snippet being included in the search result document when the measure of relevance of the first snippet to the webpage exceeds the measure of relevance of the second snippet to the webpage, and the second snippet being included in the search result document when the measure of relevance of the second snippet to the webpage exceeds the measure of relevance of the first snippet to the webpage.
10. The system of claim 9 , wherein determining the measure of relevance of the first snippet to the webpage includes: determining the measure of relevance of the first snippet to the webpage based on at least one of: a quantity of the plurality of sub-pages included in text of the first snippet, a quantity of candidate sub-pages, corresponding to the webpage, that could have been used to generate the text of the first snippet, a length of the first snippet, or quality scores associated with the plurality of sub-pages.