My favorite writing group is folding.
I've been involved there for a little over a year, writing reviews, submitting my own work, and generally enjoying the hell out of getting to interact with a group of like-minded novice writers. It's rare to find a group that is so supportive of one another, and where everyone is seriously trying to improve their own writing, and helpfully critiquing others writing.
Now the site owners are shutting it down, and it really, really sucks. It's not their fault by any means. They've done a stellar job of maintaining a wonderful, supportive, active site. They've put in a great deal of time effort and money, and generally recieved very little thanks in return (If you ever come over here, THANK YOU NIC AND CHRIS!!) However the site traffic has been dying off steadily until we are down to about a dozen regulars, and they feel they can no longer support it.
Frankly I feel guilty because I am one who frequently drops out of the community for up to a couple of weeks at a time, and then comes back. Usually I'm only a consistent commenter when I have stuff of my own to put up, though I do review more than is simply necessary to post. I read lots of the stuff, and review a good bit when I'm active, it's just that I'm only active when I have something going myself. So even though I know my specific participation, or lack thereof, did not kill the forum, I can't help but feel I was a contributor to the problem.
Sigh. I hope I can maintain contact with some of these people. They really were a wonderful group to hang out with.