What are the chances that you will be checking someone's profile at the exact time he is reading a PM? Kind of random I think and, even so, you'd only learn that a private message has been exchanged and not its contents. Not exactly a major breach of privacy. I did however see that one of our regular posters was logged onto
www.donkeys-and-leatherqueens.com whilst I was checking his profile so maybe it pays to be careful.