"Social Networks" -- the peculiarity of this ubiquitous term rarely ever draws attention. But in the history of networks, the microsocial approach in sociology is a surprisingly late event. Starting with Jacob Levy Moreno's inauguration of sociometry in the 1930s, microlevel actor networks form a crucial part in a twofold genealogy of knowledge. My presentation therefore focuses on the co-evolution of sociological theory, statistics and the rise of the digital computer. What is the relation between network visualization and non-visual logic of matrices and the databases which are now powering the massive social networking sites? How has American Sociology been constructing the scientific facts that today inform the relational approach to our lives? And finally, what power relations are inscribed in all those everyday sociometric appliances and gadgets of the network society?