An e-mail address. Your account user ID will be your e-mail address. This will be used to send you your password should you forget it. IF you don't have an e-mail address you can get a free e-mail account from
Google.
NOTICE E-mail accounts provided by yahoo.com routinely reject messages from Silent Dismissal. Be advised that if you have a yahoo.com e-mail address you will likely not receive any messages, including password recovery information. The use of yahoo.com accounts is strenuously discouraged.