A bunch of years ago, a local provider and I were swapping some emails when I get this one that had been an ongoing conversation with her and another guy. Obviously she had screwed up and sent the reply to me instead of him. The problem was this moron had used an email service that had his real name embedded next to username. A quick search had his info plastered all of the internet, including wife, kids etc...
I sent him an email letting him know about this so he could at least pull the name association. But the one I"d gotten had gone back/forth at least 10 times, so either he was really obtuse, or just didn't think it was a bad idea for someone to have any leverage.
At the time I didn't think much of it, but then recalled the provider in this situation at one point asking me my real name, which I declined to give. So hopefully the guy didn't have any lasting issues from this transgression.