A routing system is described herein for intelligently routing actions directed to any one of a collection of user devices that are associated with a user. In operation, the routing system receives a request from a source entity to perform an action. The routing system determines a mode of carrying out the action that involves use of one or more user devices, selected from the collection of user devices. It then instructs the selected user device(s) to carry out the action. In this manner of operation, requests that are directed to an individual user device are no longer necessarily carried out by that individual user device. The routing system chooses the user device(s) to carry out the action based on current context information together with relationship information extracted from a user graph.