As for asking questions you deem inappropriate? How does one know? Within reason of course IE: asking what sexual position you like when that's not already a topic of conversation. I think most people gauge other people's reactions based on what their own would be. If you've noticed any of my own posts here, I'm a pretty open person... and freely share especially when I think it might help someone. I really can't think of much that would offend me if asked... not anything seriously asked that is. Now, if I thought someone was asking flippantly to play with or embarrass me, I would simply call them on it or ignore them and consider the source/true intentions.
I don't remember asking you anything but will, surely, try not to jump your boundaries.
Edit: Just wanted to add that I do, in a way, understand what you're saying... but, I have experienced similar with "Fs." I mentioned on another thread that I have two "F" email buddies and they write asking something personal... what I think or feel on it... I answer and they never reply back. Talk about being used! But for what has always been my question there. Am I something to get their curiosity fulfilled with? What are they doing with the information they asked for? Do they have any thoughts about what I said? Its really curious mode of behavior to me.