Similar to Aussie Oz, I found this place via Freeminds. I started out lurking, to learn more about my wife's religion from an outsider's point of view and how they look at marriage and divorce when she first threatened to take the kids and leave. The information about custody cases was chilling, but also helpful in heading off a nasty custody fight and getting to a place where we can cooperate on the parenting, instead of fighting about it.
I stay because there are many smart, like-minded people to interact with, because it's a place where good support can be given as well as received, because it's a place to vent when that's necessary, because it's a place where expressing your opinions and thoughts is not only allowed but also encouraged, and because here you can disagree with somebody without having to hate them.