This does mean that you cannot sign-in if you don't have your phone in reach, for instance if you misplaced it, if it was stolen, or if you just forgot it at home. While you don't have to remember a password anymore to sign-in if you are using the new feature, you do need access to your mobile phone to sign-in instead. It takes care of weak passwords that users set often when they create accounts, protects accounts against hacking, phishing or brute-force attacks, and will likely reduce support requests in regards to lost passwords or hacked accounts. Yahoo Account Key improves the on-demand password password sign-in option that Yahoo launched earlier this year by doing away with passwords completely.
