This will be my first one in Milwaukee, so I can only tell you about the Springfield, MO, ones I've attended. Anywhere from 2 to 10 people show up and drink coffee and chat about anything and everything. The conversation usually starts with something book-related, because at first that's the only thing that people know they have in common, but then it just goes every which way as everybody gets to know each other. And we often traded books. That felt a little awkward whenever we met in a bookstore coffeeshop, but none of the store people ever gave us any grief about it.