Dale,
I think you'll find the post count has nothing to do with anything other than that's where a majority of owners landed. There isn't another active Newmar owners forum that I know of like, say, Winnie and Tiffin have. There are a few smaller ones but not many.
I am also a moderator on another forum; it's a brand specific forum yet it's the largest forum in its class on the net. There are other brand specific forums with 1/20th of the traffic. Many of our members don't own the brand of the forum, they just like the info and socialness of it. All that means is it's the place where everybody landed.
