Lots of members here, a majority I'd say. Read the agreement note at the top of the page. Its a little more involved than that. And the club is more than just some free tech advice on a forum. I'm not too good at explaining it, I'm sure someone will chime in. I recommend joining COG.
+1. Dave hit the nail on the head. It is kinda hard to explain. I've been a member over ten years and still can't explain it. I've made some long term, close friendships through COG. Good people. Great events. My suggestion is to attend a rally and find out. In fact, come to the national rally in Vermont, look me up, and I'll buy you a cold beverage.
COG was started pre-internet, so it is and has been much more than just a forum. It's a bonifide AMA chartered club, and while all work is performed by club volunteers to keep costs incredibly low, the annual dues you mention goes to cover the cost of member benefits like the member directory, magazines, newsletters, event subsidies, etc. The club's forum continues to be available for all to use at no cost.
There really no need to continually rehash Rick's decision to return control of the concours.org domain back to the club. The agreement Dave referenced speaks for itself.