How do you make a back-up account?

Honestly, I don't think it's allowed, but many people do. It's not really a big deal. I think you have to use a different email. Why do you need one?

Ya, I think you can, but they're highly discouraged. Also the F4 can tell from your IP address if you have multiple accounts, and they can shut them down if they're being used just for ratings, or if someone uses one to be outspoken on. I've seen people be banned for both uses.