This chapter discusses the role of online knowledge mediator, an entity that occupies an intermediate position in a knowledge transfer/exchange between a source and a receiver, and whose task is to assist and facilitate the knowledge transfer process, when performed through the use of Internet-based technologies to a significant degree. In the present rapidly evolving world of Internet, many types of virtual knowledge mediators continue to come out with different features and functions. Despite their growing diffusion, little effort has been devoted to examine their practices thoroughly. In light of this, the chapter aims to develop an analytical framework that could be of use to a deeper and more systematic investigation of these new economic agents. It is a two-dimensional framework, since it is based on two complementary, conceptual views of the knowledge transfer process, that is, the cognitive and the economic one.