8. A server for processing a search query, the server comprising: a storage device that stores: a plurality of application representations, each application representation being a data structure representing a different application and including one or more features of the application, the features of the application being extracted from one or more documents obtained from one or more respective sources, each document relating to the application; and a search index that indexes the plurality of application representations, each application representation representing a different application and including one or more features of the application; a processing device that executes a query processing module, an initial set determination module, a set reduction module, a result processing module, a scoring module, and a post processing module; the query processing module being configured to: receive the search query from a partner; determine a set of subqueries based on the search query; and extract query features of the search query from the search query; the initial set determination module being configured to identify a pre-consideration set of application representations from the search index based on the set of subqueries; the set reduction module being configured to determine a consideration set of application representations from the pre-consideration set based on one or more result features of the identified pre-consideration set of application representations; and the result processing module being configured to determine an initial result set of application representations based on the query features and result features of the application representations in the consideration set, the initial result set including a set of application representations, each application representation including features of a respective application and query/result features of the respective application, the query/result features defining features of the respective application in view of the query features; the scoring module being configured to: determine a score for each application representation in the initial result set of application representations based on the query features, the result features, the query/result features, and one or more machine-learned scoring models; and determine a ranked result set based on the scores of the application representations in the initial result set; and the post-processing module being configured to provide the ranked result set to the partner.
9. The server of claim 8 , wherein the initial set determination module is configured to identify an application representation from a search index that has a feature implicated by at least one of the set of subqueries.