But user created individual lists don't scale, do they? Isn't this the exact same as Twitter lists users create and maintain? I follow a few Twitter lists but I barely maintain them, it is time consuming. Correct me if I'm misunderstanding here. (That happens often)

I totally agree with you about community and creating a web of trust. I'd say we should have communities by themselves. If NIP-51 supports lists, it can be a list of people that follow a focused community. So, instead of following individuals, you follow a topic. #hashtags work kind of well but I still don't think that's the best way to go about this. 

My goal: follow a topic where a group of experts post notes we can interact with.