How do you develop policy and governance over your Atlassian products in a large organization?

[Brant Schroeder]

We have a very large organization with competing needs.  Atlassian has been a great product to bring different units, departments, areas, etc. under one umbrella for project management and service desk operations.  It is important to keep the system stable and performing well which leads to my question.  How are you developing policy in your organization that supports this but still leaves enough room for units, departments, areas, etc to accomplish what they need?  Do you have any governance in place?  If so is it made up of a larger group then the unit supporting the application?