Tracking flu outbreaks through Google

Google's philanthropic division has revealed a tool that predicts flu outbreaks across the United States using search trends. The idea is simple: When people get flu-like symptoms, they use search engines like Google to search for information and cures for these symptoms. They've proven, as it can be assumed, that there is a link between the actual number of people having the flu, and the sheer numbers of searches for flu-like symptoms. Turns out that search engine data can actually predict flu outbreaks up to 2 weeks before the Center for Disease Control and Prevention (CDC) reports it. The NY Times has a great picture showing this trend:
So what does 2 more weeks of knowing about an outbreak give us? Why is it important? From their blog:

For epidemiologists, this is an exciting development, because early detection of a disease outbreak can reduce the number of people affected. If a new strain of influenza virus emerges under certain conditions, a pandemic could emerge and cause millions of deaths (as happened, for example, in 1918). Our up-to-date influenza estimates may enable public health officials and health professionals to better respond to seasonal epidemics and — though we hope never to find out — pandemics.

Here is graph for New Jersey. Looks like we're getting closer to an outbreak... So currently this is limited to the United States, but obviously this can be expanded to other countries as well. It also doesn't have to be limited to the flu. Think of the possibilities: it can be used by health agencies worldwide to prepare for the worst. Apart from the privacy issues, I think its fantastic how collecting search engine data can be used in such a useful way.