10. The computer program product of claim 8 , wherein the changes include a modification of a resource associated with the first user, and wherein generating the revised search result comprises: determining that the modification causes the resource to satisfy the first search query; and adding the resource to the first index search result.
8. A computer program product, tangibly stored on a computer-readable medium, operable to cause data processing apparatus to perform operations comprising: updating a computer searchable index of a corpus of resources from time to time to generate an updated index for use by a search engine to provide index search results to search queries, the search results for any search query being based on a most recently updated index; recording in a computer readable memory change data specifying changes made by users affecting resources in the corpus, including recording for each change a respective user making the change, the recorded changes occurring so late as not to be reflected in the most recently updated index; receiving a first search query from a first user and a corresponding first index search result based on the most recently updated index, wherein the first index search result comprises resources indexed in the most-recently updated index that satisfy the query; and searching the change data recorded in the memory to identify any changes to the corpus of resources made by the first user that relate to the first search query and if any such changes are found, generating a revised search result from the changes and the first index search result and providing the revised search result to the first user as a response to the first query, and otherwise providing the first index search result to the first user as a response to the first query.