Relationships in an e-society: small versus large groups

From the editor's summary of an article in Nature by Palla et al. (PDF here):

The dynamics of social groups as they interact electronically is central to how modern society operates. A study of patterns of information exchange between two groups of individuals — collaborating scientists and cell phone users — has been used to devise an algorithm that relates information exchange to group stability. The data show that small groups have a few strong relationships at their core. And as long as these persist, the clique remains. But for large communities, continuous change is the key to stability. These findings offer a new view on the fundamental differences between the dynamics of small groups and large institutions.

Palla et al.'s abstract:

The rich set of interactions between individuals in society results in complex community structure, capturing highly connected circles of friends, families or professional cliques in a social network. Thanks to frequent changes in the activity and communication patterns of individuals, the associated social and communication network is subject to constant evolution. Our knowledge of the mechanisms governing the underlying community dynamics is limited, but is essential for a deeper understanding of the development and self-optimization of society as a whole. We have developed an algorithm based on clique percolation that allows us to investigate the time dependence of overlapping communities on a large scale, and thus uncover basic relationships characterizing community evolution. Our focus is on networks capturing the collaboration between scientists and the calls between mobile phone users. We find that large groups persist for longer if they are capable of dynamically altering their membership, suggesting that an ability to change the group composition results in better adaptability. The behaviour of small groups displays the opposite tendency—the condition for stability is that their composition remains unchanged. We also show that knowledge of the time commitment of members to a given community can be used for estimating the community's lifetime. These findings offer insight into the fundamental differences between the dynamics of small groups and large institutions.