5. The system of claim 1 , wherein: the tracking component is operable to store click data on search results provided to users by the client system in the result selections logs stored on the client system.
5. The system of claim 1 , wherein: the tracking component is operable to store click data on search results provided to users by the client system in the result selections logs stored on the client system. 11. The system of claim 5 , wherein the tracking component is operable to store click data that comprises information about user interactions with presentations of search results, including information identifying document results that were presented in the presentations but not clicked.