Zune sings viral tune with song sharing credits

This made me go, wow. I wonder how long will take Apple to offer something similar? Adrants reports Microsoft's Zune app will allow users to share songs which then self-destruct within three days. If the friend buys the song the sender gets a Zune credit.Now I'm thinking, how many music accounts am I going to want to manage? Pandora, iTunes, Zune...?