Doesn't work for me - I can add a new email address, but when I sign out and back in it's vanished. Feels like they might have disabled parts of the account management system.
The site is very buggy indeed. But it is possible to change the primary email adress if, when you are prompted to retype your password, you "type password and click button by mouse, not by "Enter" key" (as the post says). Maybe that would work for you...
