Everyone is worried about the H1N1 flu this season.  This already in addition to the regular flu strain that kills thousands every year.  Google developed this trending product to track the spread of flu worldwide.

We have found a close relationship between how many people search for flu-related topics and how many people actually have flu symptoms. Of course, not every person who searches for “flu” is actually sick, but a pattern emerges when all the flu-related search queries are added together. We compared our query counts with traditional flu surveillance systems and found that many search queries tend to be popular exactly when flu season is happening. By counting how often we see these search queries, we can estimate how much flu is circulating in different countries and regions around the world. — Google Flu Trends

How accurate is it?  Good question.  I’ll let this graphic speak for itself.

This should be an interesting year to track the flu.  It is worth a bookmark in your browser.

Check out Google Flu Trends