It may be benign and even mildly useful, but SEEMS creepy. Google has announced it now tracking the flu by using searches for keywords like "flu," "fever," "thermometer," and so on. It uses information gleaned from your browser and computer (IP address, MAC address, service provider) to identify an approximate location. The data will then be passed on to the Center for Disease Control. A test last year was apparently good enough that they are doing it again this year.
Google swears the data is anonymized, but don't be surprised to see ads for pharmacies and Theraflu (TM) pop up as you search the Web for a flu remedy. Google and the CDC both announced, "...this is just the beginning." What's next? Google dispatches an order of chicken soup to your house? The Feds send you a quarantine order telling you to stay home for three days? Your data is sent to the TSA (Transportation Safety Agency) which then meets you at the airport and forbids you to fly because you might give others on the plane the flu?