New models encourage legal file trading.

Peer-to-peer network providers Wurld Media and PassAlong Networks unveiled updates to their digital music services, both of which have been authorized by the music industry.

The services feature a user-compensation model to encourage legal file trading. Users are able to search for tracks on hard drives, like other P2P services, but require them to purchase tracks before using them. Each user identified as the source of a purchase gains credits which can be exchanged for free music.

Wurld Media officially launched its Peer Impact P2P service, with its first retail partner--the Army & Air Force Exchange Service. The AAFES has agreed to promote the Peer Impact service by distributing its software CDs, gift cards, and other program information through its 150 physical retail stores and in-store radio and television network. The AAFES services more than 15 million active National Guard, Reserve and retired military personnel.

Meanwhile, PassAlong Networks unveiled its new p2pRevolution platform, a business-to-business service that allows users to create branded, customized music community applications. Companies can use the software to offer their exclusive content to members, issue event notifications and allow users to trade protected files via e-mail and instant messaging services.