According to Twitter, they estimate that maybe about 10,000 accounts were affected. While 10,000 users isn’t exactly small, compared to the number of active Twitter users, we suppose it could have been worse. “The bug had the potential to expose the email address and phone number associated with a small number of accounts (less than 10,000 active accounts). We’ve notified those account holders today, so if you weren’t notified, you weren’t affected.”
As Twitter points out, if you were affected you should have gotten the email about it, but if you weren’t then don’t worry about it. They also add that nothing serious came from this bug and that user accounts are still safe. “While this issue did not expose passwords or information that could be used directly to access an account, it serves as a reminder to us all about the importance of good account security hygiene.”
To that end, Twitter has encouraged users to check up on the security of their accounts, such as by enabling two-factor authentication so that in the event someone manages to guess your password, they still won’t be able to login.