Ark nailed it already. But if you go here and under Selections expand "Range and Edgeloops", there are gifs showing it in action. Works with edges and polygons.
Actually there are a bunch of polygon reduction tools in Zbrush that would give you this look with a few clicks. Zremeshes, DecimationMaster are just a few to mention.
You could always use Tesselation modifier, but that doesn't help since it acts with all the polygons. Useful for cubes, but lackluster for anything else.