Because now, with this idea we can take a random sample of people, have them nominate their friends, those friends would be more central, and we could do this without having to map the network.
因为，有了这个概念， 我们就选择一个随机人群， 让他们提供他们的朋友， 他们的朋友就更加中心， 这样我们就能选择网络的中心，而不用描绘整个网络。