The greatest one is IDump4You.com, which purports to "take the messiness out of any breakup," and where you can pay a small fee to have the web site break up with someone for you. There are different tiers of service, from the $10 basic quick breakup call to the $50 divorce call. Personally, I think this is an awesome way to dump a sociopath.....in fact, if you visit the site and click on "psycho" in the upper navigation bar, you'll find an audio file dated 8/11/10 called "Kara dumps Matt." (That must have been the best $10 that Kara's ever paid in her life.) I just about fell out of my chair laughing as I listened to Matt.....hmm.....sounds so eerily familiar, even down to the way he talks.
As far as maintaining your online accounts such as Facebook and Twitter after a breakup, I think it's crucial to change all of your passwords. And to re-visit all security settings on all of your accounts, especially any blogs. On social networking sites like Facebook, you'll want to go through your list of friends and eliminate the ones who have any ties to your ex-abuser, especially his relatives. Even if your ex isn't a member of the same sites you are, it's wise to be as careful as possible.