Our security systems only allow a single instance of any given username. In other words, the username you choose for your account must be unique across all of our users.
If you attempt to create a new account with a username that is already in use by another user, we will present an error message to let you know. If you are a new user, and this is the first time you are signing up, simply dismiss the popup by hitting OK and then enter a different username before you tap the Sign Up button again. It may take a few tries to find a username that no one else is using.
If, on the other hand, you already have an account based on the username you are trying to use, then you should be tapping the "Log In" link at the bottom of the screen rather than the "Create Account" button. Note that you can log in with either your username or your email address.
Another source of confusion for some of our users is the fact that you can log in with Facebook instead of creating a full email/password account. If you have logged in with Facebook in the past, then make sure to log in with Facebook again now or you will not see any of your data.
And finally, if you know your email address or username but don't remember your password, you can visit our Login screen and use our easy "Forgot Password" link to reset your password. This feature will send an email to your inbox with a link that will let you select a new password.