Homophily in social relations results from both individual preferences and selective opportunities for interaction, but how these two mechanisms interact in large, contemporary organizations is not well understood. We argue that organizational structures and geography delimit opportunities for...

This is a descriptive study of the structure of communications in a modern organization. We analyze a dataset with millions of electronic mail messages, calendar meetings and teleconferences for many thousands of employees of a single, multidivisional firm during a three-month period in calendar...