I found a ridiculous bug for the comments notification system. If I comment on someone else's question thread, I'm notified of any reply to the particular answer or question I've commented on. However, if I commented on my own question thread, I'm not notified of any comment activity at all. It's extremely annoying that I've to go check each and every question I asked just to review if there's been any activity.
EDIT The problem is more localized than I thought. In the couple of questions I posted on Ask Ubuntu today, I was notified of the comments to the question, but I missed the notifications of comments in the answers I received even though I commented on them.