I understand that some folks a re really touchy about giving out personal info.
real e-mail is a requirement.
1) so that you can set up your account
2) so that I can write you letters if you've been bad.
3) is not visible to general public, but can be accessed by messaging, as Ken may have said.
4) notification of upgrades, cancellation of account, etc.
Age? sex? Location? These need not be required fields. I would just lie about my age, anyway.
I like location, for if I am traveling, I can set up a visit with other members.