1. A computer-implemented user interface method of presenting results of a search customized using content preferences learned about a user, the method comprising: receiving a user input action for interacting with an application on a user device; in response to receiving the user input action, sending query information to a search engine, the query information including user information, the user information including (i) context information describing an environment in which the user input action was received, the context information adapted into a syntax understandable by the search engine, and (ii) a user signature representing content preferences learned about the user; generating customized search results by receiving a set of search results and auxiliary information from the search engine in response to sending the query information, the auxiliary information including information describing attributes of each search result of the set of search results that led to each search result being chosen by the search engine; ordering the set of search results based at least in part on the auxiliary information; and presenting, to the user, the ordered set of search results customized using the content preferences learned about the user.
1. A computer-implemented user interface method of presenting results of a search customized using content preferences learned about a user, the method comprising: receiving a user input action for interacting with an application on a user device; in response to receiving the user input action, sending query information to a search engine, the query information including user information, the user information including (i) context information describing an environment in which the user input action was received, the context information adapted into a syntax understandable by the search engine, and (ii) a user signature representing content preferences learned about the user; generating customized search results by receiving a set of search results and auxiliary information from the search engine in response to sending the query information, the auxiliary information including information describing attributes of each search result of the set of search results that led to each search result being chosen by the search engine; ordering the set of search results based at least in part on the auxiliary information; and presenting, to the user, the ordered set of search results customized using the content preferences learned about the user. 10. The method of claim 1 , wherein the search engine includes a recommendation engine, the recommendation engine recommending search results based on at least a portion of the user information.