13. A method for determining recommendation data, comprising: extracting a first set of keywords from a set of user action logs that occurred prior to a predetermined time point; extracting a second set of keywords from a set of user action logs that occurred subsequent to the predetermined time point; merging at least a portion of the first set of keywords and at least a portion of the second set of keywords to obtain a third set of keywords; matching, using one or more processors, at least one keyword in the third set of keywords with a database of data that can potentially be recommended to a user; and in the event that a piece of data in the database is determined to match the at least one keyword from the third set of keywords, determining that the piece of data is to be recommended to the user.
13. A method for determining recommendation data, comprising: extracting a first set of keywords from a set of user action logs that occurred prior to a predetermined time point; extracting a second set of keywords from a set of user action logs that occurred subsequent to the predetermined time point; merging at least a portion of the first set of keywords and at least a portion of the second set of keywords to obtain a third set of keywords; matching, using one or more processors, at least one keyword in the third set of keywords with a database of data that can potentially be recommended to a user; and in the event that a piece of data in the database is determined to match the at least one keyword from the third set of keywords, determining that the piece of data is to be recommended to the user. 19. The method of claim 13 , wherein merging at least a portion of the first set of keywords and at least a portion of the second set of keywords includes: identifying a duplicate keyword that is found in both the first set of keywords and the second set of keywords; and determining a combined weight value for the identified duplicate keyword based at least in part on a weight value of the duplicate keyword determined for the first set of keywords and a weight value of the duplicate keyword determined for the second set of keywords.