That advertising revenue is not turning out to be as good as was initially expected, and now WMG is getting angry about the widespread use of its content on the site and the low revenue it is receiving for it. It has indicated that when the current deal is up, it will seek a new agreement with MySpace Music or pull its music from the service completely.
The fact that advertising is doing worse than was expected might signal that MySpace Music is not doing very well at all. It already has some measures in place to cut costs, such as a prompt after playing four songs that asks a user if they are still there. If the service is a financial hole for MySpace, there is only so long it will go on before they decide to drop it.