Use edge loop as curves: the better curves (obvious

Well this one might be pretty obvious, but never seen it to full extend.
You can use subdivision edge loops as a replacement for curve based modeling, wich is imho even better than what some applications offer.

Yes I know I suck doing tutorials, and a video would be a better to demonstratee the feature. Also this is more directed to users comming from other application, where this workflow simply does not exist.