The Open Data Commons provides a set of open data licences that enable organisations and individuals to make their data legally open — free for anyone to use, reuse, and redistribute.
The Open Data Commons licences, developed in 2009, were the first open licences designed specifically for data. They have been widely adopted and used with users including some of the largest and successful open data projects in the world, such as Open Street Map, Open Corporates, OpenSpending and Farm Subsidy.
In addition, the Open Data Commons licences have spurred change by others in this area — for example, inspiring Creative Commons to update their licences to cover data (in Creative Commons version 4.0 released in 2013).