Core networks provide access to a broad range of social support [2, 12-14]. However, the small number of social ties that make up a core network are also likely to be densely connected and the people to be highly similar – a trend that scholars call “homophily” [18]. Core network members are likely to share many social characteristics, including interests, beliefs, and opinions. This type of network is ideal for access to broad social support and opinion validation, but generally is less than ideal for access to unique information or diversity of opinion [3, 19].

The more numerous, weaker social ties outside of the core network are the most diverse.  These ties are typically formed and maintained as a result of participation in diverse social settings, including neighborhoods, public spaces, and voluntary organizations. Scholars have found that these diverse networks provide specialized social support and access to novel information and resources, which has been shown to assist in search processes, such as finding a job [20, 21]. Individuals who have more diverse networks tend to be more trusting [7], demonstrate greater social tolerance, cope with daily troubles and trauma more effectively, and tend to be physically healthier [22]. However, some researchers, including Robert Putnam of Harvard, have found that participation in social settings that support diverse networks, like neighborhoods and voluntary groups, has declined in the last quarter century, and that has contributed to lesser network diversity. Does the use of new information and communication technology (ICT), including the internet and mobile phone, contribute to this decline?

Some fear that internet activities in the home may substitute for participation in neighborhood and public spaces. Time spent online may replace time that would otherwise be spent socializing with ties and in places outside the home. Others suggest that the internet provides new opportunities for interaction with diverse social ties. The Pew Internet survey examined these issues: Is the use of ICTs associated with less participation in neighborhood and public life? And, in turn, does internet and mobile phone use constrain the diversity of people’s social networks?