As more communities recognize the power and possibilities of sharing public data online, there is an increasing need to articulate what it means to open data -- and how to create policies that can not only support these efforts, but do so in a sustainable and ambitious way. To this end, we are releasing the second version of Sunlight’s Open Data Policy Guidelines. Originally authored last summer and informed by the great work of our peers and allies, the Guidelines are a living document created to help define the landscape of what open data policies can and should do. For this latest version, we’ve reordered and slightly rephrased the Guidelines’ 32 provisions for clarity. We’ve also grouped them into three categories as a way of demonstrating that open data policies can define What Data Should Be Public, How to Make Data Public and How to Implement Policy.