Oh, and the link to Ultrarunning? There isn't one. I was only kidding.
BUT WAIT!! On second thought, many of us have indeed used duct tape to hold together our gear, or on our feet to prevent blisters. I've tried the foot thing and frankly, I'd rather have the blisters.
That said, there are many elaborate schemes using duct tape for the blister thingy. Just Google duct tape + blisters.