Almost everyone has gone through this – a registration form that requires you to type an email or password twice. Personally, I find it pointless and annoying. This method was designed to prevent mistyping errors, which is understandable, considering users cannot see what they are typing in. Password field is masked for for security reasons, so that snoopers can’t see them. It is assumed when the user types it twice the chances of a mistake is smaller.
But is it? I like the view (and I agree with it) posted in the article by Smashing Magazine, quoted below.
The articles is worth a proper browse as it includes other valuable UX tips regarding simplifying log-in and sign-up forms.
In reality, though, this allows for greater error, because it forces users to type more. They can’t see the characters they’re inputting, making it difficult to know whether they’re typing the right password each time. A more efficient approach would be to ask users to type their password in once, but then include a box they can check to unmask the password, so that they can check it. This option could reduce the number of text fields and decrease the work that users have to do to sign up.
http://www.smashingmagazine.com/2011/05/05/innovative-techniques-to-simplify-signups-and-logins/