11. The method of claim 7 , further comprising: maintaining, in a database, a reverse index of sentences that relates each topic to a sentence from the plurality of data sources in which the topic occurred.
11. The method of claim 7 , further comprising: maintaining, in a database, a reverse index of sentences that relates each topic to a sentence from the plurality of data sources in which the topic occurred. 12. The method of claim 11 , wherein identifying one or more sentences from the plurality of data sources that include one or more of the topics associated with the keyword included in the search query comprises: searching the reverse index of sentences using the one or more topics associated with the keyword included in the search query; and identifying one or more sentences related to one or more topics associated with the keyword included in the search query.