7. A computer-implemented method comprising: receiving at a question-and-answer application a request to display a content item with which one or more topics are associated; identifying a first set of topics of a plurality of topics by performing a first look-up operation with a first database table to identify topics associated with the content item as indicated in the first database table; identifying a second set of topics of the plurality of topics by performing a second look-up operation with a second database table, the second look-up operation to identify any topics into which a topic in the first set of topics has been merged; identify ones of the plurality of topics that have been merged into the second set of topics; for each topics into which a topic in the first set of topics has been merged, identify at least one of a question and a user associated with the topic; for each of the question and the user, merge the questions and the users on an associated question table and user table, respectively; and provide a list of questions and users associated with the second set of topics topic to an application logic component.
7. A computer-implemented method comprising: receiving at a question-and-answer application a request to display a content item with which one or more topics are associated; identifying a first set of topics of a plurality of topics by performing a first look-up operation with a first database table to identify topics associated with the content item as indicated in the first database table; identifying a second set of topics of the plurality of topics by performing a second look-up operation with a second database table, the second look-up operation to identify any topics into which a topic in the first set of topics has been merged; identify ones of the plurality of topics that have been merged into the second set of topics; for each topics into which a topic in the first set of topics has been merged, identify at least one of a question and a user associated with the topic; for each of the question and the user, merge the questions and the users on an associated question table and user table, respectively; and provide a list of questions and users associated with the second set of topics topic to an application logic component. 9. The computer-implemented method of claim 7 , wherein the request is for a question to which the topics are associated.