When your Real Estate agent not only read the same book you did and also knows the author who lives in the same area, you know you are in the right place to live.
Here is what the author, Fritjof Capra wrote about this :
the system of shared values and beliefs creates an identity among the members of the social network, based on a sense of belonging.
Cultural identity also reinforces the closure of the network by creating a boundary of meaning and expectations that limits the access of people and information to the network. Thus the social network is engaged in communication within a cultural boundary which its members continually re-create and renegotiate.
–The Hidden Connections