Originally posted by DaPi

I now find that manually "subscribing" generates e-mails when there are posts to the thread: no matter what my user profile says for "Use 'Email Notification' by default?" and even if I don't post in that thread.

You're receiving email for every post, whether you're subscribed to that post or not, even when you don't post to the thread? This is probably a silly request, but would you check your user cp and see if you are subscribed to a forum?