Do you actually log into the forums and check the thread every time you get a new notification? Because it only will send one then doesn't send another until you actually read the thread.
Haven't had it forget I'm subscribed other than when the thread gets recreated though so I can't help you there. :\
Yeah, I pretty much do every time I'm not playing something. I leave my mail open while I'm just mucking about. If I'm just surfing anyway might as well check when I get a new notice.
Not really that many other topics interest me currently, so if I get a notice its almost always this thread (and the previous threads).
Most threads I subscribe to run their course and fall off the front page (or are shifted to the Suggestion Forum AKA Where Threads Go To Die) so posts dry up pretty fast. But there's always someone posting on this thread.
It just struck me as odd since I keep having to resub every week or so that now I'm not getting notices properly either.