Yahoo was not hacked. Another site was compromised and the credentials were used to try to log in to Yahoo accounts that also used the same credentials. A lot of morons use the same credentials on more than just Yahoo.
No they didn't. Use the same username and password in two places. If one gets hacked the other gets hacked. Yahoo was not compromised.
Yahoo was not hacked. Users used the same password on an insecure website and all the hackers had to do was try the same password at Yahoo. Yahoo doesn't deserve any blame.
Get the facts right yourself. The users used the same password in two places. The other place, not Yahoo, was hacked. Then the hackers attempted to use the same credentials on the Yahoo account. This stuff happens all the time. Non-event.
Some non-Yahoo company got hacked and the morons that signed up for that company used a Yahoo email address and the same password as their Yahoo account. DON'T USE THE SAME PASSWORD EVERYWHERE.