Professor Michael Macy, a co-principal investigator of CDSS(Center for Digital Social Science), has just published his research "The Strength of Long-range Ties in Population-scale Social Networks" in Science. This paper was introduced as follows: It seems reasonable that we would have the closest, strongest ties with people in our immediate social network and that the ties between networks would be weaker. However, Park et al. discovered strong ties that spanned extreme network (not geographic) distances in 11 culturally diverse population-scale networks on four continents—encompassing 56 million Twitter users and 58 million mobile phone subscribers. Although they are fairly rare, strong ties between networks could be important for the spreading of ideas or disease.

Patrick, Park, Joshua Blumenstock, and Michael Macy. 2018. "The Strength of Long-Range Ties in Population-Scale Social Networks" Science 362: 1410-1413.

http://science.sciencemag.org/content/362/6421/1410