Generally speaking, I think a strong, healthy group can override the disruptive effects of a single individual. But in some cases, Joel, I think you're right. One bad apple can spoil the bunch. As for a surge of newbies into a ongoing group. That's an interesting dilemma. If the oldtimers are outnumbered by the newbies (who may have a different agenda), has the group evolved into something else? The oldtimers may complain, but who's to say that the new atmosphere of the group is "wrong." The "good old days" don't last forever.