Social Form of the Commons
From the Commons - Typology of Stefan Meretz :
"The social form describes the way of (re-)production and the relations that humans commit to each other when doing so. Three social forms of (re-)production have to be distinguished: commodity, subsistence, and commons.
A good becomes a commodity, if it is produced in a general way for the exchange (selling) on markets. Exchanging has to occur because, in capitalism, production is a private activity and each producer produce separated from the others and all are ruled by competition and profit searching. The measure of exchange is the value, which is the average socially necessary abstract labor being required to produce the commodity in certain historical moment. The medium of exchange is money. The measure of usage is the use value being the „other side“ of the (exchange) value. Thus, a commodity is a social form, it is the indirect exchange-mediated way of how goods obtain general societal validity. Preconditions are scarcity and exclusion from the access of the commodity, because otherwise exchange will not happen.
A good maintains the form of subsistence, if it is not produced in a general way for others, but only for personal use or benefit of personally known others (family, friends etc.). Here, exchange does not occur or only for exceptional cases, but the good is relayed, taken, and given—following any immediately agreed social rule. A transition form to commodity is barter, the direct non-money mediated exchange of goods.
A good becomes a commons, if it is generally produced or maintained for others. The good is not exchanged and the usage is generally bound to fixed socially agreed rules. It is produced or maintained for general others insofar as it neither has be personal-determined others (like with subsistence) nor exclusively abstract others with no further relationship to them (like with commodity), but concrete communities agreeing on rules of usage and maintenance of the commons." (http://www.keimform.de/2010/01/11/commons-in-a-taxonomy-of-goods/)