I treat the voting arrows as if they meant (1) as well, and in addition to that, if something is at 0 or worse and isn't in fact a waste of time, I'll vote it b

I treat the voting arrows as if they meant (1) as well, and in addition to that, if something is at 0 or worse and isn't in fact a waste of time, I'll vote it back up. Downvoting something you disagree with kills a discussion, IMHO.