Originally Posted by schnee
Super wide backswept part with awesome leverage and balance for flying downhill, narrow forward part to lower you and move your weight forward for cranking uphill. Think of it as bar ends without the awesome theatrics if you brush up against a tree at high speed.
Of course with almost 70cm wide bars you're going to be brushing up against a lot more trees in the first place and in my experience the only thing bar ends do is place the theatrics BEFORE you've smashed your pinkie rather then afterwards.