The diaspora knowledge networks (DKN) - associations of highly skilled expatriates willing to contribute to the development of their origin countries- have emerged in the 1990s. They provide a new option with regards to 3 policy areas: Innovation/ S&T, Migration and Development/ Cooperation, for both the North and South. A new actor in the recent and developing transnational arena, DKNs have been received with some suspicions, doubts and even citicisms on their real, effective ability to perform a development role. Recent evidence convincingly dismisses excessively sceptical approaches and shows the actual and potential importance of such kind of networks. They are numerous and many of these, especially in Asian cases, have had an outstanding positive effect. A survey of existing visible DKN and historical analysis on the Indian IT growth and expansion do show the original and irreplaceable developmental action of these networks. However, the experience also shows the erratic activities, limited results and precarious life of many DKN. This fact does question the dynamics of such networks: do they have autonomous effects or are they strictly context dependent? What are the market and/ or policy impacts on their developments? This presentation draws on the actor/ network sociology to explore the way that action shapes the context and therefore results of transnational activities and relations in the making. In particular, the theory of translation and the concept of interessment (intéressement) are used to explain constructive strategies for DKN. In the process of building sustainable diaspora networks, traditional entities - such as state, national organisations, public local institutions as well as firms, NGOs and intergovernmental organisations- may be involved. They can find there a new field of expansion and the reproductibily of some DKN' successes is a challenge for all.