Hess and Ostrom detail the complex interdisciplinary definitions of "commons" and "public domain," establishing the discourse in the work of Scott Gordon in 1954 and Anthony Scott in 1955, who introduced economic analysis to fisheries, a natural resource that had traditionally been the domain of biologists. "Their two articles are credited with outlining the conventional theory of the commons." Hess and Ostrom also note the application of game theory as a way of rationalizing commons dilemmas in which "appropriation from common-pool resources is frequently represented as a one-shot or finitely repeated, Prisoner's Dilemma game. Since appropriators are viewed as being tapped in these dilemmas, repeated recommendations were made that external authorities must impose a different set of political regimes and property rights on such settings. Some recommended private property as the most efficient form of ownership. Others recommended government ownership and control. Ostrom and Hess note that the political-economy literature had, until recently, not considered the possibility that the appropriators of common pool resources would find ways to self-organize their use of the CPR. The ability to self-organize institutions for collective action that transform Prisoner's Dilemma games into Assurance Games, the obstacles to self-organization, and the strategies different groups have used to overcome these obstacles are the central themes of both Hess's and Ostrom's work. It is particularly important to note that Hess and Ostrom look to fisheries and irrigation arrangements precisely in order to bring empirical human reality to the abstractions of game-theoretic models. In turn, they use the principles that emerged from empirical observation to make theoretical models.

Hess and Ostrom emphasize that although all resources have other attributes, an important insight into the nature of public and private aspects of common pool resources can be gained by considering a matrix where excludability is plotted against subtractability: "Recognizing a class of goods that share these two attributes enables scholars to identify the core theoretical problems facing individuals whenever more than one individual or group utilizes such resources for an extended period of time. Using "property" in the term used to refer to a type of good, reinforces the impression that goods sharing these attributes tend everywhere to share the same property regime. As discussed below, this is certainly not the case."

Consider a two by two matrix in which the column on the left represents low subtractability and the column on the right represents high subtractacility. The row on top represents difficult excludability and the row on the bottom represents easy excludability. Comparing the rows and the columns, four combinations of attributes become visible:

• Goods that are low in subtractability and difficult to exclude appropriators are public goods such as sunset and common knowledge.
• Goods that are low in subtractability but easy to exclude are toll or club goods such as day-care centers or country clubs.
• Goods that are highly subtractable and difficult to exclude are common-pool resources such as irrigation systems and libraries.
• Goods that are highly subtractable but easy to exclude are private goods such as doughnuts and personal computers.

Different property regimes have been used with varying degrees of success in regard to each class of goods, from communal or state ownership to private ownership. Hess and Ostrom emphasize the situational importance of every human institution by disclaiming the possibility that rigorous analysis without reference to the actual situation can yield any formula for assigning a property regime to any particular class of goods: "Examples exist of both successful and unsuccessful efforts to govern and manage common-pool resources by governments, communal groups, cooperatives, voluntary associations, and private individuals or firms. Thus, no automatic association exists between common-pool resources with common-property regimes - or, with any other particular type of property regime." Together with attacking the confusion between the nature of a good and a property regime, Hess and Ostrom analyze the confusion between a resource system and the flow of resource units, the confusion between common-property and open-access regimes, and the confusion over what property rights are involved in "ownership."

Consideration of the governance of common pool resources, the authors note, moved from natural resource systems and human-made resources to such diverse goods as "surfer's waves, sports, national budgets, public radio, traditional music, indigenous knowledge, air slots, campus commons; urban commons [apartment communities and residential community associations, streets, parking places, playgrounds, reclaimed buildings etc.]; highways and transboundary transportation systems, the Internet [domain names, infrastructure, information, acceptable use policies]; tourism landscapes; cultural treasures; car-sharing institutions, garbage; and sewing.

Turning to the common-pool resource aspects of information, the authors distinguish between the interdependent but separate artifacts such as books, articles, web pages, databases, computer files; facilities such as private and public libraries and archives, digital libraries, e-print repositories, the Internet, or local-area networks; and content such as knowledge, information, and data.

For the past few centuries, a social machine has evolved to gather, store, and transmit knowledge; information stocks and flows are at the center of this enterprise. Until recent decades, scientific and scholarly information has been recorded, transmitted, and stored in journals, books, articles, academic and public libraries. Fair Use doctrine enabled libraries to provide inexpensive or free access to bodies of knowledge. The digitization of information and extension of copyright laws have brought about radical changes in the way scientific and scholarly knowledge is handled: "Since 1995, the development of distributed digital information through network browsers has radically c hanged many of the traditional institutions of scholarly communication. Research information is moving much faster and much farther, often bypassing the normal publication process. While it is true that recent commodification and privatization of research information threatens the future of libraries' freedom to collect and distribute information, it is only one part of the story. Recent legislation, such as the Digital Millennium Copyright Act, the Sonny Bono extension Act, the proposed legislation of the Uniform Computer Information Transactions Act (UCITA), may all adversely affect the costs, access, and availability of scholarly information."

Libraries are threatened because the publishers of scholarly digital information are seeking more money and more control while library budgets shrink. Librarians such as Clifford Lynch and legal experts such as Lawrence Lessig and Jamie Boyle have analyzed the forces that could make public libraries and public scholarship into anachronisms like scribes and illuminated manuscripts. Hess and Ostrom point at a countermovement that counters enclosure through technologies that enable collective action:

"In great contrast with the new legislation increasing copyright and patent restrictions, encouraging contract over property law with the constraints of embedded licensing agreements, is the international E-prints "revolution" that is making scholarly research freely accessible in unprecedented ways. The movement officially began with the mounting of arXiv.org at Los Alamos National Laboratory. Developed in 1991 by physicist and information specialist Paul Ginsparg, it was designed to serve as a repository for digital papers in physics and mathematics. By 1993, the site had received around 500 submissions. By September 30, 2001, the site had received 174,842 submitted papers. "The papers are free but unrefereed, requiring scholars themselves to judge the accuracy and quality of the work. This archive is the first that actually changes the representation and visibility of the scholarly record. The average number of site users range from 60,000 to 160,000 per day." There are hundreds of other digital archives. The Digital Library of the Commons http://dlc.dlib.Indiana.edu/ is both an e-print repository for self-archiving as well as a traditional digital library. An example of an effective grassroots initiative is that taken by the Public Library of Science, a nonprofit organization of scientists dedicated to making the world's scientific and medical literature freely accessible "for the benefit of scientific progress, education and the public good."