Then it's up to the RIAA to (1) come and find every single instance out there, (2) get access to the instance, (3) find copyrighted content and (4) demonstrate that is beyond fair-use.
In Sweden as an example, it's OK to share with a small group of friends[1].
[1] https://translate.google.com/translate?sl=auto&tl=en&u=https...
I do think that federated services will finaly set media free. But I also expect that copyright holders will try their best to kill a few servers that are big enough to catch their attention.
Arr matey