accountable for in August of 2013 was breached during their unfortunate hack. To this day it is still thought to be a state-sponsored attack. Read country based like China or Russia as example.
It is news worthy again for most people are creatures of habit and like very simple passwords. This is bad. Or using the same security questions and again, this too is bad. If you still do, then you will probably have bad experiences sooner than later.. Here is why.
The information took in this attack was
Dates of birth
Unencrypted safety questions
Unencrypted safety answers
Hashed passwords md5 (easily crackable)
What can be done with that information? Almost everything. From a yahoo account recovery standpoint, or yahoo account take over.
So what should we do?
Any password you used for Yahoo during 2013 abandon it please. Make a new one!
Any security questions you used on Yahoo and other sites abandon and make new ones.
Most people that don't use yahoo mail, or yahoo anymore would think 'hey I should just delete that old account anyway.'
You probably shouldn't. Yahoo recycles their email addresses. So after 12 months some stranger could use that recycled yahoo account of yours to phish your other accounts you created long ago to slowly take over your digital life with the stolen information listed above. And that just won't do.
So log into the account at least twice a year, change the password when you do, and update your security questions!