Two forces are in tension as the Internet evolves. One pushes toward interconnected common platforms; the other pulls toward fragmentation and proprietary alternatives. Their interplay drives many of the contentious issues in cyberlaw, intellectual property, and telecommunications policy, including the fight over network neutrality for broadband providers, debates over global Internet governance, and battles over copyright online. These are more than just conflicts between incumbents and innovators, or between openness and deregulation. Their roots lie in the fundamental dynamics of interconnected networks. Fortunately, there is an interdisciplinary literature on network properties, albeit one virtually unknown to legal scholars. The emerging field of network formation theory explains the pressures threatening to pull the Internet apart, and suggests responses. The Internet as we know it is surprisingly fragile. To continue the extraordinary outpouring of creativity and innovation that the Internet fosters, policy-makers must protect its composite structure against both fragmentation and excessive concentration of power. This paper, the first to apply network formation models to Internet law, shows how the Internet pulls itself together as a coherent whole. This very process, however, creates and magnifies imbalances that encourage balkanization. By understanding how networks behave, governments and other legal decision-makers can avoid unintended consequences and target their actions appropriately. A network-theoretic perspective holds great promise to inform the law and policy of the information economy.