What you are describing is what I call string piecing. It is an excellent way to use up all your scraps. I never heard of using a 72" strip. I have always done it with a 6" or 7" square. You can also sew the strings on the diagonal which makes it interesting and fun when it's time to sew the squares together. Check out www.Quiltville.com. There are some ideas there for string quilting.
judyjo