Internet law and policy discussions worldwide are converging on the idea that the private sector has a shared responsibility to help safeguard free expression online. This article advances those discussions and makes a significant contribution to the related literature by synthesizing Internet governance concepts with those of content management and with normative theories regarding the social value of freedom of expression—all to the end of better understanding the implications of privately governing speech in a networked society. First, this article examines the emergence of the “networked public sphere” that has distributed the production of expression and renegotiated power relationships among individuals, state actors, and digital intermediaries. Second, to put in concrete terms the idea that intermediaries are regularly conducting “private speech regulation,” this article outlines the chain of digital intermediaries that make up the Internet’s basic infrastructure, shedding new light on the chain by employing a classification system developed originally to discuss different types of intermediaries and how they facilitate speech. This article uses the same classifications to discuss how the intermediaries can constrain speech. It also places these discussions in the context of affirmative First Amendment theory, which says the highest purpose of freedom of expression is to maximize individual participation in the public discourse. Finally, this article concludes by commenting on the history of corporate power over the public discourse and by calling on intermediaries to be transparent regarding their content-governance practices.