Online learning systems are the norm in today’s educational institutions. However, students also use social networking applications for learning, and we seek to understand the use and effectiveness of such informal (social networking application based learning) systems on learning. We analyze the design characteristics of formal and informal learning systems, in an educational environment, to develop and test a model of their impact on learning outcomes. We find students attention, volume, velocity, access to information, and their degree of control over their use of the learning systems drives their learning success.