In terms of communities where you can get the most qualified person on a topic to reply, I think Quora would also qualify, and to a limited extent, Twitter.
Quora really seemed nice until they started publish everything I did there. I also think they had a real name policy. (At least thats how I remember it.)
They might have fixed that now but I feel it would take quite some effort for them to make them feel safe again.
Reddit has a tendency to gain so much momentum that companies can't ignore people that are having problems like this. In that case, you often see a rep from the company log in and start triageing the situation.
Don here is clearly much more on top of the situation than that, but my point is that any big social site ends up seeing this with enough outrage.
I don’t think that facebook facilitates this well. Since you have to go out of your way to find a discussion there. And there is no “right now” feeling if you do find a relevant discussion. But here I just visited the home page of what I consider a general newsfeed and we’re talking to their new owners.