It could be some things changed when the new forum software went live, although that's been more than a year now.
By default you will get emails when any thread you have been part of gets a reply. But you won't get emails about other forum activity unless you specifically ask for it.
I think you went into your settings and checked all the boxes to get email notifications, but you still need to specifically tell the forum what type of content you want notifications of. (hence the "watch" instructions above)