A tremendous volume of information is now available on the World Wide Web (web). Researchers have begun to tap this resource, and reference web sites in their publications. However, web-based sources may not be available in the given location when readers attempt to access the referenced material. This article considers the longevity and malleability of web-based information sources, reasons for the loss of referenced sources, and how using this knowledge resource may affect the academic tradition of building cumulative knowledge.