Dutch Safety Video.

For copyleft to have any revolutionary potential it must be Copyfarleft. It must insist upon workers ownership of the means of production.

In order to do this a license cannot have a single set of terms for all users, but rather must have different rules for different classes. Specifically one set of rules for those who are working within the context of workers ownership and commons based production, and another for those who employ private property and wage labour in production.

A copyfarleft license should make it possible for producers to share freely and to retain the value of their labour product, in otherwords it must be possible for workers to make money by applying their own labour to mutual property, but impossible for owners of private property to make money using wage labour.

Thus under a copyfarleft license a worker-owned printing cooperative could be free to reproduce, distribute, and modify the common stock as they like, but a privately owned publishing company would be prevented from having free access.

Dmytri Kleiner: Copyfarleft, Copyjustright and the Iron Law of Copyright Earnings.