1. A system for determining recommendation data, comprising: one or more processors configured to: extract a first set of keywords from a set of user action logs that occurred prior to a predetermined time point; extract a second set of keywords from a set of user action logs that occurred subsequent to the predetermined time point; merge 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; match 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 at least one keyword from the third set of keywords, determine that the piece of data is to be recommended to the user; and one or more memories coupled to the one or more processors and configured to provide the one or more processors with instructions.
9. The system of claim 1 , wherein to merge 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.