The Google Flu Trends statistical model was created and validated using rates of ILI, which is a nonspecific syndrome that is not necessarily caused by influenza virus infection, but used for decades as an indicator of the burden of outpatient influenza illness. Any nationwide surveillance using internet key word search is likely to be most representative if the search engines being monitored has widespread use. As the popularity of a particular internet search engine wanes, so too may the overall accuracy of disease activity estimates using its data. Also, the stability of internet key word surveillance relies on consistency of internet search behavior [19] , as well as search term use between geographic regions and over time. Changing media trends, word search choices, and cultural make-up of regions and over time may also affect the representativeness of internet search surveillance.