Stephen King tweets a question: "What if dead people started tweeting."
That's actually a topic of one segment of the latest This American Life.
A troll decided to impersonate an author's dead father on Twitter.
He knew a lot about her because the info was available in scattered places on the net. She interviewed the guy to find out why he did it.
Not saying it wouldn't make a good Stephen King story.
Actually, for some time now, I've had a cronjob set to tweet for me after I die. Sadly, yes, there have been false positives when I'd been offline for too long, but I'm alive to work on that.
You can add links to comments by selecting a word, clicking the link icon, and pasting the URL. Here's a howto. Makes the result much more usable. ;-)