I would be remiss not to add that US mail is protected by the First Amendment (even if ‘unsolicited’ 
). That is why I use the postal service sometimes. Unlike message boards, if someone has a bee in their bonnet about something, they just have to live with it.
And BTW, I sometimes even get positive replies to my letters (which always have my return address IAE). Most of the time though, I get no response whatsoever. So I don’t even know how they really are received. 