It's not surprising that people search for information about the flu when they're sick. Google found a way to tap this trend and use it to estimate flu activity by region. They discovered that search trend data was actually about two weeks faster than traditional CDC methods of flu outbreak tracking.
Google Flu Trends will give you an estimate of the current outbreak level in the USA or break it down state by state. You can also see trends from past years and search for a place to find flu shots near you.
Google Flu Trends is on the Web at www.google.org/flutrends.