I did the same thing. Posting a question doesn't make it at ALL clear if it's done so. Do you NEED to tweet it? Otherwise, posting a question just leads to a form where you can submit (another?) question.
The UI could be a bit clearer there.
The same thing happened to me and I'm still not sure if my question was entered or not. I can't find anywhere that lists the questions I've asked.
I'm not seeing where you did that. Which AMA or question or username is it?
I'm not seeing it show up either - strange. I wonder if there's an approval system before the questions are public.