Once the Artist / Composer has some music they want the world to experience, they can become a member of the POLR and sign up. The process of signing up must be as simple and as streamlined as possible, similar to the process of signing up for a typical owned streaming service that has become a norm for many consumers.
One challenge of this system is that of verifying that the person registering themselves and the song are, in fact, the creator / composer of the song. To prevent gaming of the system by nefarious imposters, a blend of trust metrics, as well as newer blockchain ID verification technology will be applied, making it as secure or more secure than other owned systems. There are many exciting decentralized initiatives in the area of ID verification.
Perhaps the most promising technology for the POLR to make use of in the realm of trust metrics and decentralized social networking would be Synereo.
Here are some links to explore the ever increasing area of trust metrics and ID verification within the realm of distributed computing and smart contracts that the POLR could make use of: