This site can explain better than I can http://www.naturalhoof.co.nz/barefootmethod.html
Barefoot trimming... you are basicly taking off a bit more hoof, and the horse is actually walking more on the bottom of the foot, the frog is of course kept off the ground. But its a trim designed to bare weight more evenly over the horses whole hoof instead of the just the edge.....basicly we don't walk on our tip toes so horses shouldnt either kinda way of thinking, its based off studies of the natural hoof structure/ condition in wild horses and zebras.
When a farrier trims he leaves more hoof on as he needs it to nail the shoes onto, this extra hoof is taken off for the most part in a barfoot trim.
Hmm hope I eplained that right,
I switched both my horses to this barefoot trim , I do it myself, and boy there hooves , epecially Banjos , keep in better condition now than they ever did with shoes...and Banjo has had shoes his whole life prior to me taking them off
love the method.