Examples include the huge success of social media giants and the typical brand-buying behavior among teenagers.
First the social networks. They have grown because we all do what other people do – but the main success factor is the fact that these are networks. Because we are related to tens of others and the others are too, exponential growth could occur (instead of lineair). We are all content providers and consumers at the same time. So the collectivity mechanism is an important part of the giant success of the social networks.
Teenagers want to create their own identity and set themselves free from their parents, without alienating from their peer group of friends. They want to be different and they want to belong. This is why they look at each other even more than adults do in buying clothing, shoes and back packs. Some brands know how to tap into these complex dynamics more than others. Still no mystery here – just teens with in general no to much money to spend.