It would help if, instead of the ambiguous up and down arrow icons, the ui provided something like a bulb to mark an interesting idea, and a zzzz to represent a

It would help if, instead of the ambiguous up and down arrow icons, the ui provided something like a bulb to mark an interesting idea, and a zzzz to represent a waste of time - or something like that. In the end, people can't help themselves, they want to express agreement/disagreement, so you'd still get some people using the buttons that way, but at least the ui would communicate the desired use.