Google Maps Flu Trends
Google is using their search technology to spot trends in possible flu outbreaks. Based on the location from which searches are performed on the word "flu" for "flu shot," Google.org has created a map of the level of possible flu activity. I’m assuming they are geolocating by IP address. The page on "How does this work" does not specifically say how it is compiled other than by millions of aggregated searches. Google has done this for allergy season and has compared their trends with that offered by the CDC.