You're right about things posted in public--I never expect (or even want, to be honest) feedback on the journal; when I want feedback, I send stuff to people privately. I figure then they can be more honest--they're not saying something with a bunch of invisible witnesses, they're talking to me privately. I feel more comfortable with that.

That's how I treat comments, too. Unless someone expressly says "Please tell me what's wrong with this and how I can improve it," I tend, in journal comments, to talk about the things I like. If something glaring strikes me, I send a private message.