Grooveshark has no legal obligation to tell their users what can and can't be uploaded. Their only obligation is to follow the DMCA procedures when they receive a takedown notice for content that is allegedly infringing.
The broader discussion here it that the cost of enforcing copyright protection should fall on the copyright owners. And it's obvious that they're not up to the task, which is another clear signal that their business models sit at odds with the current state of technology.
The broader discussion here it that the cost of enforcing copyright protection should fall on the copyright owners. And it's obvious that they're not up to the task, which is another clear signal that their business models sit at odds with the current state of technology.