1. A method for facilitating media playlist generation based at least in part on media library inventory information provided by a plurality of program participants, said method comprising: transmitting, from a program participant's client device, data representative of media inventory in a media library of the program participant and which comprises identification data of individual media items presently contained in the inventory of the media library regardless of the individual media item's source; and receiving, by the program participant's client device, media item similarity ratings that have been compiled based on cumulative data collected from a plurality of program participants and in which the cumulative data comprised identification data of individual media items contained in media libraries of the program participants regardless of each individual media item's source.