Google's predictions of flu trends haven't been accurate recently: http://commonhealth.wbur.org/2013/01/google-flu-trends-cdc

I see the point of the article, but it is dated January 13, 2013...which isn't recent.

That would have been last flu season, which is about as recent as evaluations of flu surveillance systems get.

Also, I saw a presentation given at an infectious disease conference...less than a month ago. Google Flu Trends appears to really break down at small spatial scales, like a single city. Unfortunately, Google is also super opaque about how it works, so it's hard to tune.

I guess NSA could run a much, much more accurate version of such service.