Can google detect swine flu ?
Apparently it might be able to. Google has launched a flu trend service that can be used to determine the trends behind a flu pandemic / seasonal flu.
The flu trends faq hints at being able to detect pandemic flu. The quote from the faq reads
How is Google Flu Trends useful for pandemic flu?
Google Flu Trends models are built based on historic flu surveillance data. When a new flu virus causes the same symptoms as seasonal flu, Google Flu Trends can detect if overall flu rates are significantly increasing. Some search queries tend to be popular exactly when flu is happening, and are therefore good indicators of flu activity.
Google tries to understand search data and its related patterns and then determines if the search was related to a flu in any way. It then maps this search to geo data to find out how the flu spreads.