This article presents recent advances in the analysis of buyer-seller networks, with a particular focus on the role of buyer power on exclusion. We first examine simple vertical structures and highlight that either upstream or downstream firms may have incentives to engage in exclusionary practices to either counteract or leverage buyer power. We then review current work attempting to revisit this issue in "interlocking relationships". Based on an ongoing research project, we show that the same exclusion mechanism arises when retail substitution is soft.