The first step (which is now already working) is that creators can create a polycentric identity and link their platforms together using the Harbor app.
If you are then subscribed to their YouTube channel, you will also see content they post on any other platform like Patreon, etc.
You subscribe to the creator, not the platform identity.
We cannot easily provide social graphs for platforms we cannot control. However, we also offer the option to make Polycentric comments where you as the commenter own your comment, rather than the platform owning the comment.
If you are then subscribed to their YouTube channel, you will also see content they post on any other platform like Patreon, etc.
You subscribe to the creator, not the platform identity.
We cannot easily provide social graphs for platforms we cannot control. However, we also offer the option to make Polycentric comments where you as the commenter own your comment, rather than the platform owning the comment.
Polycentric is an open protocol https://docs.polycentric.io/ https://www.youtube.com/watch?v=KLoCtRzTkJQ&t=0s and you are free to create any social graph you might want to.
I hope this answers your question sufficiently.