One embodiment of the present invention provides a system for generating a message. During operation, the system receives user interaction event data. The user interaction event data describes explicit or implicit interactions of a user with a web application and/or mobile application. Next, the system modifies a graph describing the user's current context associated with the user based on an analysis of the user interaction event data, as interpreted by the system learning from previous processing of user interaction event data. The context graph includes information about the user's state, behavior, and interests, and some or all portions of the context graph may be shared between users. The system determines a set of rules associated with a group of users that includes the user, and then applies the determined set of rules to any context graph associated with the user to generate the message.