Yahoo has been reviewing ways to improve the security of our member accounts, eliminate abuse and reduce the time needed to recover a password. Mobile is a secure way to solve all 3 of these issues.
We will never use mobile numbers for anything other than verification purposes and share this personal data with other companies.
We’re currently testing our registration page and will provide updates.12 year Yahoo customer commented
Except it doesn'tt actually do anything to improve security, you mean because people thesse days feqwuently change numbers. IIt just adds a new security hole.