I feel one of the facets that is not mentioned in talk of “Social Groups/Clubs” fracturing forums is that it can also be used to go in the other direction and bring isolated groups together to reduce redundancy.
I am building a forum for a hobby that has IRL clubs but also has need and use of a ton of universal knowledge base.
So by offering a members only space for a local groups to operate on my forum for things that are specific to their club (discus meet ups, recommend local resources, host calendar), I get a automatic influx of folks for the shared spaces (general forum knowledge base, how tos, galleries, etc). By giving them a controled space of their own for their paid members and a customizable landing page, i allow them to get off FB or needing to have a site of their own, increasing the user base of my shared areas, making it more useful to all.
So for me, its not a large group splintering off, is a way of gathering up a large number of location specific groups so that they can consolidate and collaborate in the areas universal to all their groups, thus having more available to them.
