Death to passwords! New Yahoo Mail protects with push notifications instead
Account Key effectively works like two-factor authentication, allowing you to authorize new logins via your smartphone or tablet. The only difference is Account Key is not a secondary back-up measure that kicks in after you've entered your password: it is the primary way you access your account.
Yahoo's approach doesn't rely on the user entering a code received from an authenticator app or SMS. Instead, when you try to log in to Yahoo Mail a notification gets sent to your mobile device without entering a password.
From there you can either hit a Yes or No button to authorize access. This is similar to how Twitter handles second-factor authentication, but again, Yahoo's approach is the primary way you will access your account.
Account Key is rolling out alongside a new Yahoo Mail mobile app that features a new look, a faster way to search for items by sender, keyword search suggestions, and an improved compose interface.
Yahoo Mail is also adding support for Outlook.com and AOL email addresses, allowing you to access these accounts inside Yahoo Mail, including on the revamped mobile app. Multiple account support must first be enabled on the desktop and is only available to U.S. users at launch.
The refreshed Yahoo Mail mobile app is available now worldwide on iOS and rolling out to Android users over the next few weeks.