Your username is unique. All members are asked to provide a username and password.
You need a username and password for two (2) reasons:
1. To maintain the security of your account. It will ensure that no unauthorized parties can access your Domain Name information. To access Member Management and Manage Domains Functions that will enable you to effectively make amendments to your Domain Name. Eg. changing contact details etc.
2. You can only access member management and domain management once you have entered your username and password.
The username and password is a secure method of keeping your domain name details private.