I would never consider posting any private mail for public view, PM or home-box, in entirety or excerpt, positive or negative, with name or in anonymity, without the express permission of the sender.

The operative phrase, to me, is without the express permission of the sender.

I agree whole heartedly with that ... now for the caveat ... I do know, however, that the recipient of a letter owns the letter and may publish it abroad as they like ... but it is not something I would do without permission of the sender. If I am wrong here about who owns a missive I hope one of the legal eagles aBord will correct me. And although I write "letter" I mean correspondence of all types, PMs, Emails, etcetera, et.al. and that ilk!
My Dad, a newspaperman for over 50 years, told me when I wrote my first letters (way back in the 1930s My Gawd but I'm gettin' old!)
"Never write anything you don't want to see on the front page of The New York Times."
Advice that stood me in good stead when I was a teenager writing to my "boyfriend."

Happy birthday to me. Happy Birthday to me. Happy Birthday, Happy Bithday, Happy Birthday to me! (unabashed solicitation for felicitations anytime as the celebration continues for the rest of the month!)

Later Edit This is meant as a general statement of *my feelings and no criticism of anyone is implied or should be inferred, *Please!* (hopping off with foot in mouth..again!)