Is username and login the same thing?
A username is a name that uniquely identifies someone on a computer system. This username/password combination is referred to as a login, and is often required for users to log in to websites. For example, to access your e-mail via the Web, you are required to enter your username and password.
Why do some websites allow you to use your email address as a user name?
By allowing the use of the same email address for multiple accounts, people could get their multiple identities, but the email address can be used to track the limited resources. This doesn’t prevent abuse, but it helps to identify the honest people. There are of course other ways to achieve this too.
Which is more secure an email or a username?
If they can determine the username or email used for an account, that account is less secure than an account that the hacker has no knowledge of. If we use usernames for authentication then we need a way to tell a user that their desired username is taken already when they are signing up.
What happens if your username is your e-mail account?
If the username and password are compromised and the username is their e-mail, then their e-mail account will also likely end up compromised. This can make account recovery very difficult unless you use something like an SMS based recovery system.
When to use email address instead of username?
Summary: keep the address as entered at registration time and use it “as is” for display and for sending emails. For comparisons (i.e. locating the user entry in the table of users, e.g. upon login), normalize the email to lowercase (with an invariant culture).
Is it better to log in with username or password?
If someone steals the database with your hashed passwords, they will also have the usernames and e-mail-addresses. Gone is the “security benefit”! So, forcing users to log in using only the e-mail address (and the password) or only the username (and the password) makes no sense.