Commons are created through the combination of a service connection (the means to connect) and the data-sharing agreements (the contract between data-provider and data-consumer).
Before a data-consumer is able to access the common, it is necessary to accept the data-sharing agreement attached by the data-provider.
The operations allowed in a common are explicitly defined in the data-sharing agreement and they include the possibility to: read, execute scripts and combine data from it and other sources.