These are good questions. I just joined yesterday. I commented on a few hubs, but I don't understand what it means to follow someone. In the little box under the comment, it says something about "follow this hub." I thought it meant to follow the comments on that particular one. I'm sure I'll follow several, but I'm just figuring it all out.
I'm sure I'll be leaving a lot of comments, because I can usually find something interesting and learn something new, even on topics about which I knew nothing before I read them.