This commentary addresses the problem of interfirm network formation from the perspective of multiple types of relationship content and of network structure. The approach builds on Burt’s (1980) typology of network structures and on a range of empirical studies on interorganizational networks. The chapter by Moldoveneau, Baum and Rowley on network evolution from an information-sharing perspective captures part of this research domain. The challenges posed by network evolution research are discussed in the broader light of multilevel analysis.