Those clubs on NC4x4 are properly constituted clubs with dues, etc. We're just a bunch of friends hanging out with soccer mom vehicles.
Seriously though, most other 4x4 forums are very Jeep/Toyota biased and don't respect Hummers very much. I only really go on NC4x4 to see what events are being organized. Only other 4x4 forum I go to is Expedition Portal. I stay clear of other forums due to the all the nonsense you have to sieve through to find the good info.