It's really a shame when someone feels they have to *demand* a certain type of contributor. Whatever happened to the fine art of lurking and downloading? I mean, that's what made Yahoo groups great. I'm all for aggressive management of spammers, but to deny lurkers a chance to catch a look and participate if they so choose is almost like a denial of freedom of speech, dude!
Nevertheless, I wish you luck. You'll have a good couple of people in your group. Until you get reported for some minor infraction because someone got PO'd.