In a massive security breach (more than a billion users affected) Yahoo reports that names, email addresses, telephone numbers, dates of birth, passwords and security questions and answers were stolen in 2013.
What to do if you ever created a Yahoo account:
1. Change your password
2.Turn On Two-Factor Authentication
3. Delete Old Accounts
4. Play It Safe Online
"Review your accounts for suspicious activity, don’t click links or
download attachments from suspicious emails, and be cautious of messages
asking for personal information."
Source: The Wall Street Journal, 12/15/16