An anti-rival good is the opposite of a rival good: it is a good wherein the more people share it, the more utility each person receives. Examples include free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

, open source software, and other information goods created through the process of commons-based peer production

Commons-based peer production

Commons-based peer production is a term coined by Harvard Law School professor Yochai Benkler to describe a new model of socio-economic production in which the creative energy of large numbers of people is coordinated into large, meaningful projects mostly without traditional hierarchical...

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An anti-rival good meets the test of a public good

Public good

In economics, a public good is a good that is non-rival and non-excludable. Non-rivalry means that consumption of the good by one individual does not reduce availability of the good for consumption by others; and non-excludability means that no one can be effectively excluded from using the good...

 because it is non-excludable (freely available to all) and non-rival (consumption by one person does not reduce the amount available for others). However it has the additional quality of being created by private individuals for common benefit without being motivated by pure altruism

Altruism

Altruism is a concern for the welfare of others. It is a traditional virtue in many cultures, and a core aspect of various religious traditions, though the concept of 'others' toward whom concern should be directed can vary among cultures and religions. Altruism is the opposite of...

, because the individual contributor also receives benefits from the contributions of others. In evolutionary biology, this mode of production and exchange is called reciprocal altruism

Reciprocal altruism

In evolutionary biology, reciprocal altruism is a behaviour whereby an organism acts in a manner that temporarily reduces its fitness while increasing another organism's fitness, with the expectation that the other organism will act in a similar manner at a later time...

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An example is provided by Lawrence Lessig

Lawrence Lessig

Lawrence "Larry" Lessig is an American academic and political activist. He is best known as a proponent of reduced legal restrictions on copyright, trademark, and radio frequency spectrum, particularly in technology applications, and he has called for state-based activism to promote substantive...

:
The production of anti-rival goods typically benefits from network externalities. Leung (2006) offers this quote from Weber (2004):
The term is a neologism coined by Steven Weber

Steven Weber (professor)

Steven Weber is a professor of political science at the University of California, Berkeley and the Director of the Institute of International Studies. He is also the editor of Globalization and the European Political Economy . He holds both an M.D...

. Although the term "anti-rival good" is a neologism, this category of goods may be neither new nor specific to the Internet

Internet

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

 era. According to Lessig, a particular natural language

Natural language

In the philosophy of language, a natural language is any language which arises in an unpremeditated fashion as the result of the innate facility for language possessed by the human intellect. A natural language is typically used for communication, and may be spoken, signed, or written...

 also meets the criteria:
The term also invokes Reciprocity (cultural anthropology)

Reciprocity (cultural anthropology)

In cultural anthropology and sociology, reciprocity is a way of defining people's informal exchange of goods and labour; that is, people's informal economic systems. It is the basis of most non-market economies. Since virtually all humans live in some kind of society and have at least a few...

 and the concept of a gift economy

Gift economy

In the social sciences, a gift economy is a society where valuable goods and services are regularly given without any explicit agreement for immediate or future rewards . Ideally, simultaneous or recurring giving serves to circulate and redistribute valuables within the community...

. See also Private good

Private good

A private good is defined in economics as "an item that yields positive benefits to people” that is excludable, i.e. its owners can exercise private property rights, preventing those who have not paid for it from using the good or consuming its benefits; and rivalrous, i.e. consumption by one...

 and Good (economics and accounting)

Good (economics and accounting)

In economics, a good is something that is intended to satisfy some wants or needs of a consumer and thus has economic utility. It is normally used in the plural form—goods—to denote tangible commodities such as products and materials....

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