Happened to me a few months back, but in my case it was a story with a great upside...and I must say, it serves me right for not changing my hotmail address. For years.
One of those nefarious algorythms out there figured out my password and sent pharmaceutical ads to my entire address book. I decided, after rectifying the security problem, to send an email to everyone in my address book apologizing and giving a little update on where I am/what I'm doing. Which pushed me to update my address book when i got dozens of bouncebacks and, even better, allowed me to reconnect with dozens of friends and former colleagues I hadn't talked to in years!
A couple of friends swear by apps that if used, will re-spam the spammers and tie up their servers with thousands of emails...can anyone recommend apps that do this and are also cheap/easy to use? I'll follow up with a couple of folks who first mentioned this to me...will repost anything useful.