Open data is data that can be freely used, re-used and redistributed by anyone – subject only, at most, to the requirement to attribute and share alike. The core of a “commons” of data (or code) is that one piece of “open” material contained therein can be freely intermixed with other “open” material. This interoperabilityInteroperability is a characteristic of a product or system whose interfaces are completely understood to work with othe... dramatically enhances the ability to combine different datasets together and thereby to develop more and better products and services.