When my fiancee cheated on me and we broke up, I unintentionally got her back with a little revenge...
She had been using my old Earthlink address as her main email for the many years we had been living together, and she had quite the address book of contacts. After we split, I was still receiving a shiite-ton of emails from everyone she knew. So I sent a mass email to her entire contact list, basically saying "After 6 years of being together, being engaged to be married, and at the same time we spent Christmas with my parents receiving expensive jewelry/gifts, my fiancee informed me that she had been cheating on me for 4 months and was ending our relationship. Since this Earthlink email address is my personal account, and my full name is even part of the email address, I would appreciate if all of you would remove this account from your contact list and never send another email to this address again."
Only one person bothered to respond to it... a deeply religious friend of her's from church. Gave me a god bless and a much sympathies. Heard from the grapevine later that she hadn't told anyone about what was going on, so she got outed from that mass email and some of those people were a little disgusted and stopped all contact with her =p
Well, I eventually stopped using Earthlink, but not for any reason relating to what happened after the breakup. I just switched to Cox Cable internet service when I moved out of Scottsdale AZ, and having a Cox email address based off your name makes it very easy for friends/family to remember it ;-)