Flusquare combines data from Centers for Disease Control and Prevention along with Foursquare to help understand the spread of the flu.
Flusquare includes a handy flu symptom checker to help determine if you have the flu (Note: It is no substitute for a doctor). If you happen to come down with the flu, Flusquare allows you to share your checkins during the time you were contagious. Other users of Flusquare can view where contagious people have been to assess their flu risk.
Flusquare also provides you with the current weekly flu activity directly from the CDC.