In advertising and content relevancy prediction it is important to understand whether, over time, information that reaches one demographic group spreads to others. In this paper we analyze the query log of a large U.S. web search engine to determine whether the same queries are performed by different demographic groups at different times, particularly when there are query bursts. We obtain aggregate demographic features from user-provided registration information (gender, birth year, ZIP code), U.S. census data, and election results. Given certain queries, we examine trends (from high to low and vice versa) and changes in the statistical spread of the demographic features of users that issue the queries over time periods that include query bursts. Our analysis shows that for certain types of queries (movies and news) distinct demographic groups perform searches at different times, suggesting that information related to such queries flows between them. Queries of movie titles, for ...