I haven't posted any reviews on any of those websites, I've heard stories where the owners have threatened legal action against patrons posting bad reviews and thereby hurting their business.
I don't want to get into that muck, I'd rather tell people on here to avoid some places that are not worth eating at.
On the contrary, I think those are the exact right places to (anonymously) post your honest feedback, as more people look there for reviews than will here, and, and to my earlier point, here could be dangerous as although somewhat anonymous, I wonder how much, and someone here got in trouble [rightly] criticizing bad service and somehow got into legal trouble.
I am interested to know what you have heard about people getting in trouble for posting their feedback, and how they got tracked down.
I think we all should be free enough to post to those sites anonymously, and here as well, otherwise people will not say anything. This point is actually fodder for a thread of its own.
Ape Shall Not Kill Ape.