Security sure is a problem for internet users.
I had a yahoo account for many years. I used a password which I thought was excellent. I no longer use it so I'll tell you what it was. I used upper case & lower case letters as well as numbers. Here was my yahoo password: DianeMA47416
Well on 12/01/2013 someone hacked my yahoo account, got all the email addresses stored in my yahoo address book & started sending out spam using my yahoo email address. Yahoo told me there was nothing I could do but close out that particular account and open a new one. I did as they said but I didn't open a new one. I can't believe someone sat for a week attempting to break my password just so they could use my address. I think Yahoo had a security breach with one of their own employees who has access to thousands of user names & passwords.
By the way after I closed the account (and alerted everyone I know) the emails had stopped. However, just this week the emails have started again. Once again I've alerted everyone. I also contacted yahoo. They say the account is not active and the emails must be 'spoofed'. They told me how I could see the area where they generated from. I did that and saw they are being sent from someone with iphone out in California. I tried to report this to the authorities, but learned they are interested only in matters where money is involved or terroristic threats.