Libraries circulating collections are a model fault-tolerant distributed system. As a whole, the system is highly replicated and far more reliable than any individual component. There is no single point of failure, no central control to be subverted. There is a low degree of policy coherence between the replicas, and thus low systemic risk. The desired behavior of the system as a whole emerges as the participants take actions in their own local interests and cooperate in ad-hoc, informal ways.
Librarians are more likely to have confidence in an electronic system if it works in a familiar way.
If libraries can take physical custody of purchased journals, in a form that preserves reader access, they can assume responsibility for future use. If a library takes custody of a copy of a Web journal, the copy can behave as a Web cache and provide access whether or not it is available from the original publisher. If many libraries do this, the caches can communicate with each other to increase the reliability and availability of the service, as inter-library loan increases the reliability and availability of access to information on paper. Librarians balance the cost of preserving access to old material against the cost of acquiring new material. They tend to favor acquiring new material.