4. The method of claim 3 , further comprising creating a sub-query histogram based on the sub-query model rankings and the number of user interactions with the responsive images.
4. The method of claim 3 , further comprising creating a sub-query histogram based on the sub-query model rankings and the number of user interactions with the responsive images. 5. The method of claim 4 , wherein determining a search phrase score comprises: determining a level of match between the interaction histogram and the sub-query histogram; and determining the search phrase score based on the level of match between the interaction histogram and the sub-query histogram.