Open government enthusiasts have looked to a variety of web-based tools, platforms and media to promote transparency and empower citizen participation in government decisionmaking. Yet, when these efforts do not fully respond to the demands of specific policymaking contexts or democratic norms, they cannot effectively level the participatory playing field. In this chapter we focus on digital innovation aimed at increasing meaningful public participation in US rulemaking. We first examine why the US federal government’s e-rulemaking strategy has not successfully addressed the barriers to effective participation. We then introduce Regulation Room, a consultation platform using purposeful design of online tools, and human support strategies, to lower participation barriers and promote stakeholder engagement in complex policymaking.