3. The method as recited in claim 1 , wherein: the search log data includes one or more of information of users, queries submitted by users to the search engine, URLs associated with the queries, and a correlation between the users, the queries, and the URLs.
1. A method performed by one or more processors configured with computer-executable instructions, the method comprising: gathering data from multiple sources, the multiple sources including search log data of a search engine and website content from an online forum website or a social network website; predicting, based on the multiple sources, topics of interest to one or more users; generating, based on the topics of interest, a set of topic-based representations from the multiple sources; generating budgets for the set of topic-based representations at least partly based on a degree of user interest that is calculated differently dependent upon a respective source of a respective topic-based representation, the budgets including a first quota of data to be selected for a first topic-based representation from the search log data and a second quota of data to be selected for a second topic-based representation from the website content, the generating includes: calculating a first degree of user interest for the first topic-based representation based on a number of unique uniform resource locators (“URLs”) that are related to the first topic-based representation and clicked in the search log data; and calculating a second degree of user interest for the second topic-based representation based on a frequency a topic related to the second topic-based representation that appears in the website content and a publishing date of a webpage that is in the website content and contains the topic; and smoothing a data budget distribution among the set of topic-based representations, the smoothing including allocating a portion of the first quota of data from the first topic-based representation to the second quota for data for the second topic-based representation, the first topic-based representation having a higher ranking than the second topic-based representation at least partly based on the topics of interest.