I did read the article you quoted. The short phrases referred to in article were common phrases and words. A password (though possibly short but maybe a sentence) I think should be able to copyrightable. It is unique, it is original (assuming you didn't use a common word, phrase or sentence) and i created it. Just because I was required to does not seem to me to exclude it from copyright. The same can be said for an email address, at least the first part up until the domain. If the actual email name is allocated (by the email provider)then I most certainly do not hold the copyright (the email provider does).

> Just because I was required to does not seem to me to exclude it from copyright.

That's not why it's excluded from copyright.

> If the actual email name is allocated (by the email provider)then I most certainly do not hold the copyright (the email provider does).

No, the email provider doesn't hold the copyright on email addresses, because those aren't copyrightable either.