The Game Master:
I had somebody who is NOT going to play (amazing how many ask and then fall through) who are the current 'players' in Chicago.
I find that is usually a good thing. I find that I do that often, having gotten a feeling from the existing interaction of the other players in a forum, or just picking up vibes. I often cannot tell what the "energy" of a particular group is until I spend a day or two discussing things with them. Only then will I be able to say "yes" or "no" to spending more time.
Sometimes different groups don't gel very well because they are composed of different people.
I find it a good thing that a group of people is self-correcting that way. =)