These answers would add to the community's content. To that end, I also think that a host, while more visible, should be as unobtrusive as possible. The exception would be that rare person who, by name recognition, or by force of magnetic personality, can bring about the emergence of a community around themselves. I think I pretty much am myself. I hide some of my personality warts, but when people interact with me, they get me.
Some folks can pull off an online persona.
I really want to know about the other people. I think that's a key element in hosting. I don't know. I wouldn't know how to teach someone to do this. My online experiences are mostly good ones.