In this chapter, we outline the techniques used in optimizing or facilitating information diffusion in social networks. We identify two problem definitions through which a broad survey of techniques in recent research is provided. Namely, we explore the problems of maximizing the spread of influence and minimizing the spread of misinformation in social networks. As different as these problems are in terms of the motivation behind them, they both rely on sub-problems that are very similar. Through our study of these two problems, we delve into more detail about the sub-problems: Sect. 2.2 model formation, Sect. 2.3 problem optimization, Sect. 2.4 large-scale data analysis, and Sect. 2.5 research trends.