Systems and methods are disclosed for improving search results returned to a user from one or more search domains, utilizing query features learned locally on the user's device. A search engine can receive, analyze and forward query results from multiple search domains and pass the query results to a client device. A search engine can determine a feature by analyzing query results, generate a predictor for the feature, instruct a client device to use the predictor to train on the feature, and report back to the search engine on training progress. A search engine can instruct a first and second set of client devices to train on set A and B of predictors, respectively, and report back training progress to the search engine. A client device can store search session context and share the context with a search engine between sessions with one or more search engines. A synchronization system can synchronize local predictors between multiple client devices of a user.