Yahoo has changed its password updating quite a bit.
If you have more than one account, it will link a message to your other account saying the password has been updated.

They also have an antihack photo avatar you can put on your page. So in the future you go to your account, and don't see that avatar then you can then suspect a hack.

I've had Yahoo for over a decade and they are very responsive to my emails. Someone made an email similar in name to mine once from stealing my credit card information from an online vendor. I sent that info to Yahoo and it was fixed within a day. It is a long story, but this person used my real name from my one real Yahoo acct...to purchase diamonds online. The diamonds company called me up, and therefore the sale did not go thru. We cancelled our credit card instantly and no other attempts were made at all. Yahoo was great and swift in helping us. (it was not their fault either, and they cancelled that other email, because it was created during the commission of a crime).

Last summer someone requested my secret questions at Yahoo and they sent me an immediate email to my other account to change my email and my secret questions within 24 hrs. Which we did and nothing bad happened. We have never had a hack into our email, and I only keep an address book there for one account. The others are empty. I think it is the address book that is the target most of the time, there. However, I have received virus attacks from emails AOL, and others from time to time. I don't open them.