One thing is for certain - the six month old MySpace Music project is throwing off a lot of cash to the labels. That's because MySpace's 75 million or so U.S. users are streaming literally billions of songs a month at various streaming rates ranging as high as half a cent per play (although most streams are likely much less). Labels are known to give streaming rates as low as half a cent per song play, and journalists have tried repeatedly to understand the rates that MySpace is paying since the volume means lots of dollars are at stake. MySpace has always guarded this information closely, since it's a competitively valuable piece of information. But there's another reason they may be so secretive - the deals they cut with the four big labels may all be very different. And the deal they cut with at least one label, Warner Music, may not have streaming rates at all. Our sources say Warner has been complaining about the deal they did with MySpace. That deal has no per song streaming cost, but includes a revenue share on advertising displayed when the song is played. That revenue share hasn't been what they thought it would be. And the staggering number of plays of songs from their catalog, combined with their newly acquired knowledge that their competitors are being paid per stream, has left them steaming mad.