How do contagions spread in population networks? Which group should the authors market to, for maximizing product penetration? Will a given YouTube video go viral? Who are the best people to vaccinate? What happens when two products compete? This paper is to provide an intuitive and concise overview of most important theoretical results and algorithms to help them understand and manipulate such propagation-style processes on large networks. The paper contains three parts: theoretical results on the behavior of fundamental models; scalable algorithms for changing the behavior of these processes e.g., for immunization, marketing etc.; and empirical studies of diffusion on blogs and online websites like Twitter.