1. A method performed by one or more server devices, the method comprising: receiving, by one or more processors of the one or more server devices, a search query; searching, by one or more processors of the one or more server devices, a corpus of documents, or information associated with the corpus of documents, based on the search query to obtain a set of search results; searching, by one or more processors of the one or more server devices, sources of specialized information, or information associated with the sources of specialized information, based on the search query to obtain specialized results, where each of the sources of specialized information include information related to one of news, stock quotes, weather, music, movies, travel, maps, images, shopping, search history, definitions, questions, patents, or a local time; providing, by one or more processors of the one or more server devices, the set of search results and the specialized results to a user; tracking, by one or more processors of the one or more server devices, parameters associated with the user's selection of results from the specialized results; constructing, by one or more processors of the one or more server devices, a probability model, based on the tracked parameters, to estimate one or more probabilities that the user will select a certain type of the specialized results for use in selecting or scoring future search results provided to the user; selecting, in response to an additional search query, certain specialized results based on the estimated probabilities; and providing, in response to the additional search query, the selected certain specialized results and other search results to the user.