Not sure if this is a bug or not, but I've started to notice that I'm not getting notifications for several of the threads I'm "watching." I tend to watch a lot of threads, so I don't always get through them in a timely manner. Wondering if the notifications expire after a while or something. But sometimes I'll visit a thread that I haven't seen in a while, after going through all my notifications, and notice there's several pages that I've never visited and never got notifications for. Hope that makes sense.