All kinds of software projects, whether open or closed source, rely on open source components. Repositories that serve open source components to organizations, such as the Central Repository and npmjs.org, report billions of requests per year. Despite the widespread reliance of projects on open source components, little is known about the social interactions that occur between developers of a project using a component and developers of the component itself. In this paper, we investigate the social interactions that occur for 5,133 pairs of projects, from two different communities (Java and Ruby) representing user projects that depend on a component project. We consider such questions as how often are there social interactions when a component is used? When do the social interactions occur? And, why do social interactions occur? From our investigation, we observed that social interactions typically occur after a component has been chosen for use and relied upon. When social interactions occur, they most frequently begin with creating issues or feature requests. We also found that the more use a component receives, the less likely it is that developers of project using the component will interact with the component project, and when those interactions occur, they will be shorter in duration. Our results provide insight into how socio-technical interactions occur beyond the level of an individual or small group of projects previously studied by others and identify the need for a new model of socio-technical congruence for dependencies between, instead of within, projects.