A recent study tracked the correlation between social groups and disease and found that the more friends a person has, the more likely they will catch a new disease earlier in an epidemic.  So, social networks is becoming a new method to track and predict epidemic behavior.  A couple blog posts on this paper have linked the phenomenon to the number of Facebook friends a person has as being an indicator but the actual study deals with genuine social networks . . . many people have plenty of facebook friends who they don’t actually know personally (friend whores that we be) and so it is very unlikely that a physical virus would travel through such digital networks so a correlation to actual disease behaviors would need to take those profiles and business based profiles into account before making assumptions on tracking disease.  The sort of social network that encourages only in-person contact sharing would be more likely to show significance (such as a school or work or small town type social network that is a closed system).  See http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012948 for the paper.

– Brian