Some more questions:
7) If I send files to my kindle using the
name@free.kindle.com email address, there will be two copies in the cloud. But if I send it to
name@kindle.com, there's only one. Also, there's a confirmation email send back to you from Amazon if you use
name@free.kindle.com, but no emails if you use
name@kindle.com. Do you know why this happens? Which email do you usually use, and why?
8) I notice that when I send mobi files to kindle, they are converted to azw. Is is normal? Why do they do that? Should I just covert my files to azw in Calibre instead?