Most slide guitarists - in fact all slide guitarists - use a bottle neck or something to slide up and down the strings, leaving themselves with no lefthand to pick the strings with. So, this guitarist decided to do it differently. It shows that ingenuity is all you need to not do it the same way as everyone else. Leading difference is what you leaders do. Because if doing what everyone else does is all you want your people to do, then you're a manager. And you need to be both - leading people into new territory, encouraging them to do new things, as well as getting the old things - what everyone else does - right, too.