1. A system for on-demand distribution of works over a communications network, comprising: a memory; a processor in data communication with the memory; a network interface in data communication with the processor; at least one catalog stored in the memory; wherein the at least one catalog is configured to reference at least a first work and a second work, wherein the first work is different from the second work, wherein each of the first work and the second work is selectable by a user from the at least one catalog, wherein a first data file comprises at least a portion of the first work, wherein a second data file comprises at least a portion of the second work, wherein the first data file is different from the second data file, wherein each of the first data file and the second data file is capable of transmission to a user device over the communications network, wherein each of the first data file and the second data file is capable of play on a software player associated with the user device, wherein each of the first data file and the second data file is encrypted prior to play, wherein at least a portion of the first data file is configured to reside in main memory on the user device at the time of play of the first data file, wherein at least a portion of the second data file is configured to reside in main memory on the user device at the time of play of the second data file, and wherein either: the first data file and the second data file each comprises at least one musical recording, or the first data file and the second data file each comprises at least one moving image; and wherein the processor is configured to require a first authorization, which first authorization is configured to enable at least one of transmission or play of at least a portion of each of the first data file and the second data file, wherein the first authorization is configured to expire with respect to both the first data file and the second data file if at least one predetermined act is not performed by or on behalf of the user within a predetermined period of time, wherein the at least one predetermined act and the predetermined period of time are the same for both the first data file and the second data file, wherein the first authorization is usable across at least two logon sessions within the predetermined period of time, and wherein the at least one of transmission or play of at least a portion of each of the first data file and the second data file is configured to be at least one of limited or inhibited after the expiration of the first authorization.