What social networks promote the spread of behavior change?

In the September 3 issue of Science Magazine a very interesting study by Demon Sentola provides supportive experimental evidence for why behavior change may be more likely in community-based approaches than in more linear health education settings. The paper reports on 6 experiments that show that  behavior change spreads more quickly, more thoroughly and is adopted more strongly in social networks with more clustering, i.e. with many interlinking ties between individuals, than in more random social networks with few casual ties between individuals. The latter social network is associated with quicker spread of infections and is regarded as more effective for spreading knowledge across societies. But these studies indicate that for behavior change, many interlinked direct social contacts may be needed to reinforce behavior changes.