This paper discusses the following four changes in how we use sources of information or representations of knowledge: (1) from tangible to intangible media--how sources of information and representations of knowledge are manifested or packaged on the Internet; (2) from books and journals to services and databases--how such knowledge packages are published and distributed on the Internet; (3) from buying to leasing--how access to knowledge packages is controlled on the Internet; and (4) from ascertaining to using, a new purpose for the catalog--how we help others to use knowledge packages on the Internet. The magnitude of these changes is evaluated, some connections to AACR2 (Anglo American Cataloging Rules, 2nd edition) are detailed, and 12 changes to AACR2 are suggested. (Contains 22 references.) (MES)