Wikipedia's policies, guidelines, and other rules can be revised edited by anyone at any time, creating a rule environment that has changed substantially over its 15-year history. Wikipedia provides a remarkable benchmark for understanding the potential and pitfalls of self-governance in a knowledge commons and empirically informing theories of networked governance and institutional analysis. Using a corpus of 725,000 revisions made to 2,012 pages about rules and rule discussions since 2001, we explore the dynamics of English Wikipedia's rule-making and maintenance over time. Our analysis reveals a policy environment marked by on-going rule-making and deliberation across multiple regulatory levels more than a decade after its creation. This dynamism is however balanced by strong biases in the attention and length towards older rules coupled with a diminishing flexibility to change these rules, declining revision activity over time, and a strong shift toward deliberation.