How do I nurture an online community that does good things?

I run a pretty successful music-centered youtube channel, and I want to nurture a community around it with a purpose. Instead of exclusively trying to propel myself into more success, I want to build a community of people doing useful things for the world.

So my question is, what is a good way of going about this? What is a good way to build a useful community on a channel that is music-centric?

All the best,

Joel “Roomie” Berghult