In spite of the large variety of technological means available today to obtain and share knowledge needed by the progress of our Society, the relation between the knowledge produced and the knowledge required is not sufficiently facilitated. This paper aims to provide a partial answer to this issue. It proposes a NIAM/ORM formalization of exchanges between producers and users of knowledge. The resulting model is used to analyse and to discuss the deficiencies of the current technologies as well as to outline some ways of evolutions for better collaborative knowledge exchanges.