Educational practitioners and theorists have long recognized that education is a social activity where people make sense of information through interactions that support internalization and externalization. Unfortunately, applying a social theory of learning to the field of e-learning is challenging. Online course management systems (CMS) are typically designed to support the traditional instructor-centered model of instruction and serve primarily as a mechanism for delivering information for student consumption. This article presents a framework and implementation for a notification system that is based on the learner's social context and personal notification preferences. The new notification system, called the Context-Aware Activity Notification System (CANS), uses the concept of social context as a filter for activity notifications to deliver fewer, yet more relevant, notifications to e-learners and provides support for tacit forms of communication through the design of its system architecture and data collection features. (Contains 5 figures and 4 tables.)