The best username will be one you will remember. However, we suggest that you do not choose a username that can be easily guessed, like your name or email address. Also, don't use sensitive information like your Social Security number. Please memorize your username and keep a written copy of it in a safe place.
Your username may be up to 128 characters long, and may include letters, numbers, and special characters (such as @, dash, underscore, or period).
If the username you want is already taken, try adding a number to the end of it, or an underscore and a number. For example, if you wanted the username BigDog but it was already taken, you could try BigDog1 or BigDog_2.
Your username is NOT case-sensitive (unlike your password, which IS case-sensitive), so if you set up your username as BigDog_17, you could also sign in using bigdog_17.
If you already have an account and you're just trying to sign in, go to the Sign In screen (there's a link to it at the top of the Account Setup screen).
Recover your username on the Forgot Username screen .