I've being experimenting with several users in my forum and there is no way I receive messages when a message is being posted to a thread i'm subscribed to. If someone just replies to a post I made it works fine, I receive the email notification for regular posts and private messages. It is just for posts in a thread i'm subscribed to (I should receive notification that a article was posted even if it is not for me right? after all that's why you subscribe to the the thread) this happens in both 1.1.8 and 1.2.0