Open Data Commons is the home of a set of legal ‘tools’ to help you provide and use open data. Open Data Commons exists to provide legal solutions for open data. In March 2008 it launched the first ever open data license: the Public Domain Dedication and License (PDDL). Open Data Commons is an Open Knowledge Foundation project run by its Advisory Council and like the Foundation is a not-for-profit effort working for the benefit of the general open knowledge community.
We've made it easy for you to make enquiries to data holders about the openness of the material they hold -- and to record publicly the results of those efforts. A vast amount of data is produced today by government, researchers and others. In practice it is often unclear whether data is openly available i.e accessible and freely re-usable without additional permission.