The pull from a group on a member to take up a certain role on its behalf. A set of people who resonate on a particular issue, and wonder whether they are permitted to talk to anybody else without screwing everything up. I tend to associate this with the 'motherly instinct', but that may be just my biased take on it. The event is memorable in that it is the first time that a contributor to the list attempted to harm another contributor by making accusations to her employer. Along the way, some folks post topics that others feel are outside the scope of the forum.
Someone criticizes the enlarging range, others defend it.
And besides, say narrow-talkers, you can talk about that other stuff elsewhere.