Yep this was a "feature" of Joomla. I shut it off Sat or Sunday after Nefarious brought it to my attention.
Quite a few people were getting these messages and they were to inform you that a new article had been posted. (that was the content of them and it was really not neccesary) and most people didn't have the right to go look at the message.
Pretty slick.
So that's turned off now.