I'm extremely active in a Prius forum http://www.priuschat.com
and have been since it's inception in mid/late 2003. That site now has well over 20k members and is extremely active and widely recognized as the
goto site about the Prius.
I have to say that it started much as this site has. Dedicated enthusiasts, well moderated to keep the piss poor attitudes in check and lots of friendly off-topic banter...if all you ever eat is your favorite food you'll soon tire of it... The variety and off-topic stuff will keep folks coming back as long as the on-topic content is solid...which is certainly seems to be.
While golf-carts certainly don't hold the intrique of a revolutionary car like the Prius, it's clear that there is a pretty large faction of enthusiasts out there. And I'm yet to find a single 'great' independent forum out there. I find the Buggies Unlimited to be pretty decent with lots of good tech support from the company, but I' always a bit tentative about those corporate sponsored sites.
HRC has been extremely cordial in letting me post my star cars forum stuff here and that kind of open mindedness is a great way to attract folks as well.
What I'm saying is I like this forum and see a bright future for it. It's the first cart forum, after my own, that I check when I get online.