I'm surprised no one seems to have commented on the lack of usernames, I think the lack of usernames may hinder adoption since it's much harder to follow someon

I'm surprised no one seems to have commented on the lack of usernames, I think the lack of usernames may hinder adoption since it's much harder to follow someone just from seeing a tweet, err note, displayed. With Substack Notes you'll need to know the user's id, or search by their non-unique name.