25. A non-transitory computer-readable storage medium on which is encoded executable program code for category-based search, the program code comprising: program code for identifying an event comprising a user interaction with an article stored on a storage device of a client device responsive to monitoring user interactions with the client device; program code for identifying an event schema describing a format of the identified event responsive at least in part to an article type of the article, the schema comprising fields based on the article type and fields that describe interactions with the article; program code for identifying a plurality of attributes associated with the identified event that correspond to the fields based on the article type and fields that describe interactions with the article, the plurality of attributes identified responsive to the article and the monitored user interactions; program code for determining at least a first category associated with the article based at least in part on the attributes; program code for storing at least a first association data record, the association data record comprising a category-article pair identifier associating the first category and an article identifier identifying the article; program code for receiving an implicit search query; program code for causing the implicit search query to be executed on a data store comprising the first association data record; and program code for receiving the first association data record from the data store.
25. A non-transitory computer-readable storage medium on which is encoded executable program code for category-based search, the program code comprising: program code for identifying an event comprising a user interaction with an article stored on a storage device of a client device responsive to monitoring user interactions with the client device; program code for identifying an event schema describing a format of the identified event responsive at least in part to an article type of the article, the schema comprising fields based on the article type and fields that describe interactions with the article; program code for identifying a plurality of attributes associated with the identified event that correspond to the fields based on the article type and fields that describe interactions with the article, the plurality of attributes identified responsive to the article and the monitored user interactions; program code for determining at least a first category associated with the article based at least in part on the attributes; program code for storing at least a first association data record, the association data record comprising a category-article pair identifier associating the first category and an article identifier identifying the article; program code for receiving an implicit search query; program code for causing the implicit search query to be executed on a data store comprising the first association data record; and program code for receiving the first association data record from the data store. 29. The computer-readable storage medium of claim 25 , wherein program code for determining at least a first category associated with the article further comprises program code for creating the category.