This thesis presents five studies on the social dimension of knowledge, with a focus on its creation and diffusion processes. Broadly speaking, the creation and diffusion of knowledge are phenomena inherent to human society as a whole. In this sense, the results of the works in this thesis can be relevant and applicable in several social domains. However, the main focus of this work is on ideas rather than specific information and opinions. A working example that has been used through the chapters in this thesis is the dynamics of scientific ideas: how they are conceived, adopted and diffused Uwithin scientific environments.