Accounts, and Passwords Under Lock
Accounts are an e-mail and a password of at least eight characters, and the server never stores it readable.
An account is now an e-mail address with a password of at least eight characters. The login screen checks the format and the repeated password before anything leaves your machine, and the server checks it again — a rule that lives only in the client is decoration.
Passwords are stored with a random salt per account and slow hashing, so two people with the same password do not leave the same trace, and a stolen file is not a list of accounts.
Your character is also saved every thirty seconds while you play, and not only when you log out: a server that stops unexpectedly used to cost the whole session.