said by nwrickert :

It's always hard to know where they get an email address. Some of them come from dictionary attacks, some from the web or usenet, some from mailing lists, some from address books on computers that they have broken into.

said by xmrocks :

To me it sounds not like a hijacked or stolen e-mail address but rather spoofing (correct me if I'm wrong). If you're sure that's it's not spoofing, then Yahoo would have to deal with it.

If it's just spoofing, (i.e. a spammer sending from her e-mail address or making it appear so), Yahoo can't do much about it and you'll have to let the spammer run their course and move on to another e-mail address to spoof.

said by danny9 :

.... How would you know for sure whether it's spoofing or not or is this something like or is a type of bot??
Thanks

said by MGD :

You can tell by examining the headers on several of the returned emails. The mail will show whether it originated from Yahoo. From your description it is most likely "spoofing", a common occurrence.

MGD

said by danny9 :

My ex, yes we're still friends, appears to have had her e-mail address stolen.
She's been getting hundreds of bounce backs from addresses all over the world.
She uses Yahoo mail and has already notified them.
They're looking into it and will get back to her in a few days.
They had her open one. A strange name and her e-mail address.
I scanned her computer with several different scanners and they all come up clean. Not even a tracking cookie. She does take good care of her computer.
My question, is there anything that could have been done to prevent this and where could her e-mail have been picked up to be used for spamming?
Thanks, Dan

said by danny9 :

Thanks to everyone who responded.
It shows I still have alot to learn about the wacky world of the web.
And because of this I think we'll have a new member shortly.
Dan

said by NormanS :

I concur with the others. A couple of years ago, spammers forged a Yahoo! Mail account email address of mine. More recently, they forged my domain; making up user names I don't have, and using them in the SMTP MAIL FROM:.