Can you explain why I only get emails from some people who answer my questions, and not others? I like to be alerted when I get a reply.

You only get email notifications to responses to posts in the "Ask a Question" forum. (And only if you specifically request it when you ask the question.) But you should see a notification on your ATP home page when there is a new response to questions asked on other forums.

It's taken me a month to understand what you were saying. Now, I got it! Finally. Thank you.