I have tagged Lauda.
Publication of personal messages without consent. User cannot be trusted
I guess you can tag me as well, since I've admitted doing the same thing in the past. I never posted anything as far as personal information, nor did I realize it was such a big deal (though I haven't posted a PM in a thread in quite some time). If the community now thinks it's inappropriate to do so, I have no problem following that. And I'm not worried about getting tagged, just wondering what the community consensus is.
It's not against the rules, but that doesn't mean it's not a reason to leave someone a neg for it--just like account selling. But my own opinion is that it's not such a violation of community standards (or even such a big deal in general) as to deserve a neg. If you send someone a PM and don't want it quoted, the best thing would be to let that be known up front.