These numbers are only used to log in, and they are not included in your e-mail address. Because there may be multiple users with the same handle on our system (i.e. jane@thisdomain.com and jane@thatdomain.com), we use the 2-3 numbers that follow your username to differentiate between accounts. Most users quickly learn these numbers after logging in multiple times. If you do forget, click "lost username/password" on the log in page to retrieve your full username.