Abstract: According to one embodiment of the invention, a free preview of a program can be provided to client computers in a multicasting system. This can allow viewers in the multicasting system to view a first portion of the program before deciding whether to order the program content. According to another embodiment, various distribution methods can be accomplished using encyrption keys to distribute program content. According to yet another embodiment, an initial viewing period can be provided to allow negotiation of the encryption keys. According to another embodiment, rules and conditions for providing content in a multicasting environment can be utilized.

Abstract: A system is described for allowing “pay by time” purchasing of digital video programming. The system provides for a variable or metered approach. A user can purchase a fraction of a program for a price different from that required for purchasing the entire program. Records of the user's viewing can be created to record, e.g., when a user started receiving a program, how long the user received a program, and when the user stopped receiving a program.

Abstract: According to one embodiment of the invention, a free preview of a program can be provided to client computers in a multicasting system. This can allow viewers in the multicasting system to view a first portion of the program before deciding whether to order the program content. According to another embodiment, various distribution methods can be accomplished using encryption keys to distribute program content. According to yet another embodiment, an initial viewing period can be provided to allow negotiation of the encryption keys. According to another embodiment, rules and conditions for providing content in a multicasting environment can be utilized.