A search engine receives user-submitted queries, determines web pages that are relevant to those queries, and returns relevance-ranked lists of references to the relevant web pages. Additionally, the search engine adds each query's terms to a query log. An automated process asynchronously examines the log and locates questions therein. For each question so located, the process determines whether that question already is contained in a database of questions maintained by an online question-and-answer system that is separate from the search engine. For each such question that is not already contained in the stored database of questions, the process automatically adds that question to the question database. As a result, the set of questions used by the online question-and-answer system grows even in the absence of any further direct question submissions by users of the system.