While Jed is right that everyone who frequents AW already knows all about why/how HE machines differ from traditional washers, I think the average citizen---who often knows nothing about washers or the products used in conjunction with them---would find it informative and easy to understand.
I used regular detergent for years in my front-loaders, but they all (including my current machine, a 2002 Frigidaire) used substantially more water than today's Hettie/Duet/LG.
For instance, I used powdered Tide ColdWater (non-HE) for over a year with excellent results. Most of the time, though, I use HE detergents; I certainly would if I had a newer, ultra-low water use machine.