I think of this like being in a group of authors. I'm involved (and have been involved in the past) in a few groups of authors, through Facebook, Twitter, Yahoo groups, or even local author groups. I've found them all to be the same, from a sociological standpoint.
A group of authors (or ANY group of people) seem to have similar types of people involved in the group. I'm going to describe them for an author's group, if they were all at a dance. I'm also giving them a label, so I can refer to them later. No one will probably fit any given category, but might cross categories.
The Salesman: This is the true salesman. They can be humble, but whatever they say, it's usually to make a sale, no matter what.
The Fixer: This person wants to fix your problems while writing about your life. They usually have their hands in more than one project at once and are overwhelmed. But they're always willing to help others.
The 'Crazy': My middle kid said I HAD to have this one in the party mix. This is the author who's a 'little out there' and talks to their characters (don't we all?). Their goal isn't really to sell a lot of books, but to share their stories with others, even though others may not want to hear about them. (Can you tell where my middle kid put ME?)
The Wall Flower: This person has written one book and is too afraid to tell anyone else about it. They stand on the sidelines, watching everyone else talking about their books, but is afraid to jump into the conversation.
The Life of the Party: Have you ever seen someone take control of a group, making everyone want to follow them? This is the life of the party. They're fun and energetic, and everyone wants to read their books. They sell a lot of books, but some of the time, the books don't live up to the hype. But they're good at making sales while you have no idea they've even pitched their books.
The Success: This is the person who's made it in life. They're worth millions and people bow at their feet. They're the celebrities and certainly act the part.
The Pushover: This person does whatever everyone else tells them to do. They want to make it, but they're floundering, because they don't know which path will take them to success, so they try it all.
The Jerk: This person puts others down to promote themselves. They can be nice, but watch out...they're nasty behind backs.
Band Members: Believe it or not, these people are part of a group at a party. They're the ones who support other authors and build them up, but forget to promote themselves.
I'm sure I missed a few, but you get the idea. Which other ones would you add?