My favorite bit from Imbens' piece:
Research related [networks] has been conducted in multiple disciplines and is a fertile area for interdisciplinary research. Sociologists have a long tradition of studying communities and social interactions, and have contributed many substantive questions to this area. They have also collected interesting data sets, as well as some statistical methodology.
Nice of the sociologists to collect some questions and data for us ...
Imbens is actually very good about paying attention to other disciplines, but I could not resist the tease.