For a long time now, Google has been interested in what we search on. I remember reading an article in late 2001 that described a visit to a Google building with a screen on which search phrases scrolled by in real time. To my great surprise one of the phrases the author listed was a search I had performed myself in that time frame. Today, someone has had the insight that people search for certain keywords because of things that are happening around them.
Public health authorities the world over try to measure the frequency and severity of various infectious diseases in order to spot epidemics and pandemics in time to do something about them. For the flu, they ask doctors to report what percentage of the cases they see each week are Influenza Like Illnesses - as this percentage rises it is safe to conclude the amount of flu in the community is rising, even though not everyone with the flu goes to the doctor and not everyone with an ILI has the flu. These numbers take about two weeks to gather and are released publicly so various levels of government and quasi government can react to them.
So the Google insight was that people search for words like "fever" or "joint pain" when they or someone they know has an ILI. (I actually don't know what search terms Google is counting - it might only be the word "flu" for all I know.) These aggregated counts are available immediately with no waiting while people tally and report, tally and report up the chain. Take a look at the correlations:
Wow! That's a pretty amazing relationship between those lines. And instant results instead of waiting two weeks could make a real difference in treating an outbreak. But I am not sure how I feel about it. It's almost creepy, yet at the same time it's very cool. How can you be sure this ability will always be used for good?