I'm used to seeing a red flag (as in, "flag this content") for alarms or issues that need reporting. But I will admit I spent several minutes the first time I saw the bell, wondering if clicking on it would make the post expire! Because that's how I'm used to seeing it in calendars & mail & so on: it tells you when time is up. Although I suppose one could argue that the bell tells you when an event is occurring, I'm just more used to alarm = "one task has completed" (eg, sleeping), with implication that new task begins. For a long time, I just avoided the bell on LJ, not sure if it'd mean I'd have to redo the comment later, or some wackiness like that, or if it'd tell me after X time that no one had replied...

Not that it gives me issues now, having been Properly Trained, but still, I always find it amusing how our brains react to, process, and then finally get indoctrinated on, new symbology.