When service systems span multiple firms, possibly in multiple geographies, they can be difficult to model effectively, as they become subject to the complex legal, economic, political and social forces of the environment in which they operate. We must consider, therefore, the structure of institutions mediating the links amongst services in order to gain an understanding of the quality of these links, and how varying link quality contributes to the overall structure and efficiency of a service system. This paper explores an approach towards studying the structure of such cross-firm service systems by critically examining the nature of the standards used to expose services to one another.