Most ISPs give e-mail addresses when you sign up for their service. We don't accept free e-mails because, frankly, people are stupid and tend to make multiple accounts to cheat.
Banning of things like Yahoo and Hotmail for signing up limits that far more, in addition to the layering of things like IP tracking.
We accept ISP, school, and work e-mail addresses, as well as webmaster/admin accounts of private domains. (: If you don't have access to one yourself for some reason, chances are you have a friend or family member who does.
You only need this e-mail address to retrieve your initial password. After that you can set a free e-mail in your OOC profile to which all subsequent e-mail will be sent (like Lost Password requests).