I was asked some questions about Private messaging being read by others, so I did some checking. The only people that can see a PM is the person sending it or the person/persons receiving it. Neither the moderators, nor the Administrator/owner can see them. If something you PMed has shown up elsewhere it may be a coincidence. However, it can be forwarded by the receiver, and even if that were blocked it can be cut and pasted. Also, if you have received one that was sent to multiple people and you click the "REPLY ALL" it will go to everyone who received the original as well as the sender.
I have left this open for anyone who wishes to ask a question or comment, however, it will only remain a sticky for 7 days.