One of the many changes that web developers are having to adjust to is that it's much harder to conceptualise and prototype a rich internet application than a simple page-by-page one. We've all been a meeting where a BA, PM or designer has tried to do this with something like PowerPoint, and have since realised that PowerPoint just don't cut it.
So, to cut long story short, here's here's a much cooler way of doing it in Visio.