I've had a couple that posted scurrilous lies about me till they got tired of it. Personal info is limited as I don't use Facebook or Twitter or any social media unless you count newsgroups and Yahoo groups. I'm sure a dedicated hacker could get into whatever files the government might have on me (i.e. security clearances and the like) but I don't stay awake wondering about it.
I have been known to write letters to the editor and even a few columns for our local newspaper, so I'm more likely to find an irate local on my doorstep. That's why God invented Smith & Wesson :-).