There is a companion to this video I am uploading to Dave now. The one above demonstrates how to use this method for a CLOSED path and the one I am uploading now is for an OPEN path. The only real difference is where you start the extrusion of the poly face. But it's a good example of a solution for a recent user forum request.
PS - I hope these little vids are helpful. I do them on the fly and so nothing is scripted and I keep in the errors so you can see what can go wrong and how to fix things. If anything I want to apologize for rambling on. These all come out longer then I intend. (smile).
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675