How do 你 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 你 have to use a different email. Why do 你 need one?

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