From the “Who Are the Influentials?” chapter of Ed Kellar and Jon Berry’s book The influentials:
There’s a value in having connections across different kinds of groups, with different interests, insights, and, probably, different demographic compositions. It brings people into contact with perspectives and information they otherwise might not obtain. It can enable them to traverse economic or social boundaries and to establish relationships with people whom they might not otherwise encounter. It builds networks that can be called on to organize support for a cause.