The Microsoft Zune may pay you for sharing a song with others if they end up buying that song themselves. As you probably know, the Zune's WiFi capability will let you send a song to another Zune user, and then that user can listen to it three times for free within three days, after which a prompt appears asking for $1 to buy it. As the rumor goes, Microsoft will give you an unspecified number of credits for passing along that song that was later bought. Then, you can redeem those credits for free music or anything else from the Zune Marketplace.
This is a great idea. If enough people buy into Zune, the product will reach critical mass, and because of this bounty, everyone will be eager to offer their song lists to others in hopes of amassing enough credits to buy more music. It's viral/incentive marketing on a micro-payment scale. If this is just a false rumor, if I were Microsoft I would do it anyway.
Zune to Pay You Back for Sharing Songs? [CrunchGear]