^ did indeed, but they also tested the net and it got even better mileage than with the tailgate up(they tested it on a white single cab dodge dakota on the interstate). but only because of less weight i would think

 

Interesting to see the info on Mythbusters testing; not what I expected. I wanted this mod bad and now maybe I'll save my money. I was even looking at the Go Industries steel mesh tailgates, for 2 to 3 hundred dollars.

One thing that would have been cool is the additional visibility backing up. However, losing more weight in the back end is just going to make this truck slip more in the rain.

 

Tailgate up at first doesn't help, but once your moving and the air in the bed is moving it creates a more arrow dynamic shape for the truck.

 

The additional weight would overcome the drop in parasitic drag. Trucks are designed to take advantage of Bernoulli's principal.

True, but nothing you will notice. Taking 30lbs off a 4,000lb truck is going to lessen the friction coefficient by a fraction of a decimal. If you want more traction, get skinnier tires.