I'm hooked on Google Trends. For example, it probably won't astound you to learn that whenever search trends peak for flu symptoms, there's a similar peak for vaccine. (See also how at some points vaccine comes first and only then do flu symptoms arise. Conspiracy theorists, the ball is in your court!) Probing this particular case further, I looked at the search trends for swine flu and vaccine. The former peaks in April 2009 and, to my surprise, vaccine actually declines over the following two months.