10. The system of claim 8 , where, when assigning the value to the particular search result document, the processing unit is further to: assign the value to one or more sites associated with the particular search result document.
8. A system comprising: an interface to receive a search query from a plurality of client devices; and a processing unit, implemented at least partially in hardware, to: identify a plurality of search result documents based on a search query, provide information regarding the plurality of search result documents to the plurality of client devices, receive information regarding selections, of the information regarding the plurality of search result documents, at the plurality of client devices in connection with the search query, determine that a particular quantity of the selections, for information regarding a particular search result document of the plurality of search result documents, is greater than a quantity of the selections for information regarding one or more other search result documents of the plurality of search result documents, assign a value to the particular search result document based on determining that the particular quantity of the selections, for the information regarding the particular search result document, is greater than the quantity of the selections for the information regarding the one or more other search result documents, the value, assigned to the particular search result document, being based on: a particular period of time, and a respective network address associated with one or more of the plurality of client devices, and use the assigned value as a measure of quality for the particular search result document for a subsequent search, the subsequent search being associated with the search query.