Sociophysics has devoted a lot of attention to social influence and opinion dynamics. Among the others, the pioneering works by Galam, where agents randomly gather in groups of different size until consensus is reached, have been used to analyze the spreading of rumors. Galam’s model however, considers only special kinds of social spaces. In this chapter we survey some of the most recent contributions on opinion dynamics, illustrate Galam’s model of rumor diffusion and extend it to consider more general networks.