13. The method of claim 12 , wherein the other user activities on the results of the previously executed search queries are interactions selected from the set consisting of: a dwell time corresponding to an amount of time between the user opening a respective document corresponding to a respective search result of a respective previously executed search query and the user exiting from the respective document; hovering over a respective search result of a respective previously executed search query; and bookmarking a resource location corresponding to a respective search result of a respective previously executed search query.
12. The method of claim 1 , wherein identifying the predicted performance function includes performing machine learning on a correlation between the scoring primitives and other user activities on the results of the previously executed search queries in addition to actual user selections of results of the previously executed search queries.