The problem here is that the private tag was broken in the initial post, which was then edited to fix it; however, the email was already sent. If you notice, in your message, it says [privatge instead of [private.
The thread is not private at all which explains why you can subscibe to it, if it were you wouldn't be able to see it and there fore should have no way you could subscribe for emails.
The second point is that the email contains a private tag which has a typo in it, therfore not being private to anyone. The default behaviour of private tags was changed recently, not entirely sure how it should behave now if you only specify a single name but that name is invalid. Ideally it should treat it the same as when it has no names.
Finally, Rigo, can we change the system back to how it was before the upgrade so that edits have no time period before they show. I would have spotted this sooner had the edit been visible, my life would have an extra 3 or 4 minutes in it.
Edit: damn you Sith. Ninjad coz I had more to say.