I just read something that seems really nice. It's even strange that it isn't already used like that. Use an email address-like identifier as pointer to an account. Let me explain.
Email addresses consist of two parts seperated by an @-sign. The first part is
the username, the second part is the domain name of your email provider. For
example, my email address is
firstname.lastname@example.org. The username is
the domain name is
By taking this approach of username@domain we can dream all kinds of other combinations that could work.
email@example.com firstname.lastname@example.org email@example.com
You see? And these could all point to all kinds of user accounts. This doesn't mean that all these addresses should be email addresses. I also don't say that they shouldn't be. For some things I would make sense, for others it maybe doesn't.