Bill Buxton talks about the difference between “Sketch” and “Prototype” in this his Sketching User Experiences. (see the summary below)
I agree sketching is an important part of the design process, but often times it’s hard to share our paper and pen sketches and get feedback from others. Following Part I of the SketchFlow tutorial, this tutorial demos the SketchFlow player and different ways designers can share their design ideas.
You can also download the video here.