As one who has belonged to several other sites over the years I can tell you that GCA.com is both normal and unique in all the best ways.
Normal:
-- Its very common for people to have disagreements, get in fights, and even develop a bit of bad blood for each other on sites like these. Sites like this are just an extension of life in that you meet some people you like, and others not so much. I don't think its any more complex than that.
-- People who tend to frequent these sites tend to be very passionate about whatever it is that brought them there, otherwise they wouldn't be spending so much time at the site...simple as that.
-- For as much some folks really love to dive in and analyze every last thing, you'd be amazed at how this is done on other enthusiast sites for just about anything you can think of. Car nuts, astromors, cheese coniseurs, star trek trekkies, beer snobs, climatetologists, and the list goes on and on. GCA.com is indeed a great outlet for people to meet birds of the same feather....because 99.99% of people have no interest in discussing these things in great detail.
Unique:
-- The camraderie here despite a few folks who can't/won't/refuse to get along is 2nd to none...it really is. Genuine folks who really care about this stuff and go out of thier way with their time and money to play and talk all things architecture.
-- The level of civility is actually pretty darn good in here and being required to post under your name is likely a big part of it. This is the only site I've been to that requires this and it works really well IMO. Without this a lot more trolling/flaming/bad behavoir would be happening.
-- Another great aspect to this site is having so many people who work in the industry willing to come on and share thier thoughts in great detail. I really appreciate this aspect of the site and hope everyone is thankful for the insight one can recieve by participating in such a forum. These guys don't have to do this and think it very douche-baggish when they get chased away with false accusations/hassling or otherwise.
-- From a content viewpoint this site is by far and away 2nd to none. The combination of interesting topics, course reviews both formal and informal, guys getting together for outings, candid discussion on just about anything, in-depth course histories, trips to the library for research, etc make for a terrific place to throw down a few stakes and call home.