The Interactive Glossary: Defining the Net

A user name is an identifier used to log into the portion of a website or computer application that is password protected. A user name may be referred to as a username, login name, account name, screen name, nickname, or handle. All of these terms refer to the same thing: an identifier that is unique to a single user of a website or application.

User names can only be used by a single user on any given system. For example, there cannot be more than one user who registers the user name ExampleUser1 for a Google account. Once a user name has been registered, additional users who attempt to register the same user name will not be able to do so, and will have to select a different user name.

The uniqueness of user names is necessary because the combination of a unique user name and password is the mechanism used by websites and computer applications to identify a specific user and authenticate access to the website or application.

A number of user privileges and services are dependent on the user authentication system:

• Creating relationships: User names are used by users to identify each other. Without unique and memorable user names, users are unable to identify each other and form relationships online.
• Authentication: A unique user name is necessary to allow a user to identify themselves to a password-protected system. When combined with a password, a user name allows a user to prove their identity to a password-protected system.
• Provisioning of resources: Access to website resources, personal information, financial data, and unique account information is all provided on the basis of an authenticated user name.
• User roles: In some password-protected systems, different users have different roles. A user's role is tied to their user name. For example, popular forums will have at least two levels of privileges: users and moderators. Users may post new discussions and reply to posts, but moderators can delete posts, ban users, and provide other types of community oversight.

Frequently Asked Questions

Can I use the same user name for more than one website?

Assuming the user name is available on multiple websites, it is possible to use the same user name at multiple websites. However, if you want to keep your activity on a specific website confidential, you should register a user name that is unique to just that website.

In addition, if you've used the same user name and password for multiple accounts, and your account information is exposed, an adept hacker can use that information to access you account at every site where you've used the same credentials. For this reason, some security experts recommend using a different user name and password for every website where you register. Practically speaking, keeping track of this many sets of login credentials is very difficult, and it is a good idea to take advantage of shared authentication whenever it is offered by a website.

What is shared authentication?

When you register with a website, you may be offered the opportunity to log in using your account from a different website, such as your Google or Facebook account. The advantage to this method of registration is that you don't have to remember a new user name and password, and your account at that site is more secure since no login information is actually stored by that website. The danger of shared authentication is that if you use a single account to register at multiple sites, and then that account is compromised, then your access to all of those websites has been compromised.

Overall, the advantages offered by shared authentication outweigh the risks, and it is a good idea to take advantage of shared authentication whenever it is offered. However, for best security, be sure to use a very secure password on the account you use for shared authentication, and to guard the password closely.