I'd love to see this. So far I've heard a lot of people make this claim yet nobody has produced any evidence of it.
I guess I am in that group, I strongly believe some of the messages I saw were originally private. Unfortunately, there is no easy way to prove this.
every time you get a facebook message, you get an email. as late as 2009, those emails included the full content of the message.
I just have to find some private post on my timeline, the corresponding email and write a blog post?
I haven't seen any of that. However, I have seen people having conversations on posts where it almost seems like the conversation belongs in an email.
Also, it is easy to be a troll by copying and pasting a section of the article.